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LESSON Significant Changes to the 2012 NC Mechanical Code DOMAIN: COGNITIVE

LEVEL OF LEARNING: KNOWLEDGE, COMPREHENSION

MATERIALS: Overhead projector or laptop computer and multimedia projector; projection screen; North Carolina Administrative Code and Policies 2009 Edition, North Carolina Mechanical Code 2009 Edition, North Carolina Mechanical Code 2012 Edition, Significant Changes to the 2012 NC Mechanical Code Full Power Point Presentation.

MOTIVATION: To educate Code Enforcement Officials on the changes to the 2012 NC Mechanical Code, as well as provide Continuing Education.

TARGET: Certified North Carolina Code Enforcement Officials, Mechanical Level I, II or III.

Goal: This class is designed to introduce certified NC Mechanical inspectors to the significant code changes found in the 2012 NC State Mechanical Code. This Lesson Plan is representative of six hours of Continuing Education.

SUMMARY: This presentation addresses the significant code changes from the 2006 IMC to the 2009 IMC including North Carolina Amendments. The 2012 NC Mechanical Code is based on the 2009 IMC. Not all changes are reflected; only those considered significant to a majority of code enforcement officials.

Significant Changes to the 2012 NC Mechanical Code Lesson Plan

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OBJECTIVE PAGE

Created By:

Janie N. Sutton, P.E.,Chief Mechanical Code Consultant

NC Department of InsuranceOffice of State Fire Marshal

(919)-661-5880 ext 237

CS Number: 1762

Presented By:(Presenter Name)

(Affiliation - Jurisdiction)Contact Information:

(Contact Address)(Contact Number)

Instructor number:(Instructor Number)

Sponsor:(Sponsor)

Sponsor Number:

(Sponsor Number)

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OBJECTIVES

1. Identify commonalities used throughout the presentation to show changes between the 2009 and 2012 NC Mechanical Codes.

a. Slide 1: Significant Changes in the 2012 North Carolina Mechanical Code

i. Explain that this presentation was created by Janie Sutton for the Department of Insurance, Office of the State Fire Marshal.

ii. The timing is allowing time for questions and discussions.

iii. The instructor is encouraged to ask for questions, and if the students are hesitant to ask, then ask them questions to get the discussion started.

iv. Major changes in the code should be discussed to determine how the inspectors might interpret the new code.

v. It is offered to instructors across the state to use in training on the changes in the 2012 North Carolina Mechanical Code to provide consistency in training and interpretation of the 2012 codes.

vi. This presentation does not cover all of the changes in the 2012 code. It covers the ones that are most extensive and a few others.

b. Slide 2: Purpose of the Classi. This course may be taken for 6

hours credit only once in a two year period.

ii. This course is not approved by the licensing board for mechanical contractors.


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c. Slide 3: Purpose of the Class (cont’d)i. Emphasize the mandatory date of

March 1, 2012.ii. The codes that have been approved

and will become mandatory March 1, 2012 are this code, the plumbing code, the building code, the fire code, the fuel gas code, the residential code and the energy code.

iii. The 2011 electrical has not yet been approved as of July 1, 2011.

iv. Check the DOI website for updates on the status of these codes.

d. Slide 4: Erratai. Read this slide and go to next slide.

e. Slide 5: Format of Presentationi. Explain that this format is designed

to make it easy to tell new code from current code, and comments from code language.

ii. As an instructor, you will need to make an exception and read the code.

iii. Then explain and discuss the code with the class.

Presenter Notes slides 1 – 5:Significant Changes to the 2012 NC Mechanical Code Lesson Plan

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End of Presenter Notes slides 1 – 5:


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2. Discuss the significant changes to Administration Chapter of the 2012 NC State Mechanical Code.

a. Slide 6: Chap.1 Administrationi. Sections 101 through 109 are changed

by the North Carolina Building Code Council to reflect North Carolina Law.

ii. There are no changes in these sections.

b. Slide 7: 110.1 General i. Read this slide, then go to the next slide

for comments.

c. Slide 8: Section 110 i. Comment on types of systems that

would be used on a temporary basis.ii. Temporary chillers and boilers are

examples. iii. You can probably think of others.

d. Slide 9: 110.2 Conformance i. Read this section and go to next slide

for comments.

e. Slide 10: 110.2 Conformance (cont’d) i. You do not need to read this since it is

not code.ii. Comment on the areas of the code that

are important for life safety and access.

f. Slide 11: Section 110 i. This is a comment to introduce the next

section of code on temporary utilities.ii. Ask the class where this might apply.

g. Slide 12: 110.13 Temporary Utilities i. Read this section and go to next slide.

h. Slide 13: 110.14 Termination of Approval i. Read this slide and go to next slide for

comment.

i. Slide 14: Section 110 i. Instructor may read or paraphrase the

points on this slide. ii. You may want to go back to the

previous slide and read it again. iii. Some inspections departments have

had difficulty with temporary permits being closed and permanent permits not being issued.


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iv. One way to control this is to require a bond for the temporary permit that is returned when it is closed out. (Suggestion only)

v. Note that each of the two previous paragraphs say that the code official “is authorized to” allow the use of temporary utilities and terminate the permit.

vi. The code official is not required to allow them.

vii. However, when the code official determines that these provisions can be met, he/she should be willing to use these provisions unless there is a good reason not to allow temporary utilities.

viii. Chapter 2 definition will not be covered here. Some definitions will be covered later.

Presenter Notes slides 6 – 14:



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3. Discuss the significant changes to the General Regulations Chapter 3 of the 2012 NC State Mechanical Code.

a. Slide 15: 301.4 Listed and Labeled

i. This part of section 301.4 has not changed.

ii. There is a new exception.

b. Slide 16: Section 301

i. Exception 2 has been added.

ii. Read the exception and go to next slide for comment.

c. Slide 17: Section 301 cont’di. New equipment designs for energy

efficiency might be new types of dual fuel appliances.

ii. Ask the class about other field erected equipment they may have seen.

iii. This helps officials share information between jurisdictions.

d. Slide 18: Section 301 cont’di. Section 105 is where alternative means,

methods, and materials are located. ii. For field erected equipment this section

can be used instead of 105. Any components or parts that should normally be listed shall be used and the design must be by a registered professional.

iii. For example, a built up air handler is typically designed by a registered professional. The arrangement is shown on drawings and the components described in the specifications.

e. Slide 19: 301.14.1 Foundation and Exterior Wall Sealing

i. This covers all types of piping and other openings. Where piping, cables, vents, ducts pass through foundations and exterior walls, the spaces shall be sealed to protect against the passage of rodents.


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ii. This section also describes how it is to be sealed.

f. Slide 20: 304.4 New Paragraph addedi. Read this slide and talk about it.ii. Ask in what Group H occupancies

could you have an appliance with an ignition source. (toxics)

g. Slide 21: 304.6 Public Garages i. This section is a clarification. Read only

the existing and new. ii. Do not read the portions that have been

deleted.iii. The next slide provides a diagram and

opportunity to comment and discuss the code section.

h. Slide 22: Section 304 (cont’d)

i. The height requirement is based on the door height, which the code official can readily determine instead of a vehicle height that might not be known at the time of installation of the appliance.

i. Slide 23: Section 304 (cont’d) i. If the vehicle can pass under the

appliance, the height shall be one foot above the tallest vehicle garage door opening.

ii. If the vehicle cannot pass under the appliance, the minimum height is 8 feet above the floor.

j. Slide 24: 304.10.3 Crawl Space Supports i. The North Carolina Mechanical Ad Hoc

Committee changed this section to clarify the requirements.

ii. Read the new code text.iii. Then go to next slide for discussion.

k. Slide 25: 304.10.3 Crawl Space Supports (cont’d)i. The unit shall be supported a minimum

of 2 inches above grade. ii. The minimum for duct clearance from

grade in a crawlspace is 4”. iii. Does this change that requirement? No.


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iv. Explain that in cases where the duct connection to the appliance is close to the bottom of the unit, the 4” above grade requirement must still be met.

l. Slide 26: 306.5 Equipment and appliances on roofs or elevated structures

i. Another clarification. Thank you! ii. Read the code text and go to next slide.

m. Slide 27: 306 New Sectioni. This is the new part from the ICC. ii. Read this code text and go to next slide.

n. Slide 28: 306 New Section (cont’d)i. Some architects have argued that the

intent of the code is for roofs that are 16 feet above grade and that the parapet wall has no effect on this section.

ii. This change clarifies that the parapet wall height is counted.

iii. If the roof is less than 16 feet above grade and the parapet wall is more than 16 feet above grade, the permanent access shall still be provided.

iv. What is meant by “periodic maintenance”?

v. Discuss what this means. vi. The intent is for any equipment that

must be periodically cleaned, inspected, lubricated, parts changed out (like filters and belts), etc. must have permanent access.

vii. Without permanent access, the equipment or appliance will not be properly maintained.

o. Slide 29: Section 306.5 i. Read this slide and go to next.

p. Slide 30: 306.5 (cont’d)i. Items 1 through 5 did not change.ii. Read item 6.

q. Slide 31: 306.5 (cont’d)i. The OSHA requirements are more

restrictive than the code requirements.ii. We do not enforce OSHA, they are

listed for your information only.


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r. Slide 32: 307.2.2 Drain Materials and Pipe sizesi. This is part of the section on condensate

disposal systems.ii. The requirements for joints and

connections have been added.iii. Read the new code text. iv. Go to next slide for discussion.

s. Slide 33: 307 Discussioni. It is expected that a mechanical

inspector would know enough about piping joints and connections to apply the provisions of Chapter 7.

t. Slide 34: Table 308.6 i. Table 308.6 is not shown here. ii. The North Carolina Committee believes

that there is an error in the last column, second type of assembly.

iii. All the other clearances in that column list 3” except for this one.

iv. The committee changed this one to 3” as well.

u. Slide 35: Section 308.7 Ammendedi. This is a comment to introduce the next

slide. ii. The North Carolina Mechanical

Committee changes Table 308.6 to apply to unlisted equipment and therefore changes section 308.7 as well.

x. Slide 36: 308.7 Ammended i. Read the text excluding the deleted text.ii. Go to next slide for explanation.

y. Slide 37: Section 308 Discussion i. If the equipment is not listed, but the

appliance label specifies a clearance, that clearance is to be used.

z. Slide 38: 312.1 Load Calculations i. Read this slide and go to next one.

aa.Slide 39: Use of Manual Si. Manual S is required in the 2012

International Mechanical Code. ii. The North Carolina Mechanical

Committee felt that this change is


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important so they brought it into the North Carolina 2012 Mechanical Code.

iii. Manual S goes into more detail on equipment sizing than Manual J.

iv. It provides sizing methods for the different types of heating and cooling equipment.

v. Is the inspector required to ask for proof that the equipment was sized using Manual S?

vi. Only if the inspector suspects that the equipment is not properly sized.

vii. The inspector has the right to ask for documentation to show code compliance.

viii. If you suspect that the load calculations were not performed and Manuals J and S were not used, you have the authority to ask for documentation.

ix. It is the decision of the inspection department whether to require calculations on all one and two family dwellings.

Presenter Notes slides 15 – 39:


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4. Discuss the significant changes to Ventilation Chapter 4 of the 2012 NC Mechanical Code.

a. Slide 40: Chap.4 Ventilation

i. Chapters 4 and 5 have quite a few changes.

ii. Many of them are simply re-organizing the chapters to more clearly divide ventilation and exhaust and to group some requirements together.

iii. Requirements on exhaust were removed from Chapter 4 and requirements on ventilation were removed from Chapter 5.

b. Slide 41: 401.1 Scopei. This change clarifies that exhaust

systems are found in Chapter 5.ii. Read the existing and new code text.

c. Slide 42: 401.4 Intake Opening Location i. The word intake was added for

clarity. ii. This section applies to intake openings

only. iii. Exhaust openings are moved to

Chapter 5.

iv. Read the code text.d. Slide 43: 401.4 Cont’d

i. These were removed because they refer to exhaust.


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e. Slide 44: 401.4 Cont’di. These requirements were revised to

apply to outdoor intake openings only. ii. The exhaust opening requirements are

in Chapter 5.f. Slide 45: 401.4 Cont’d

i. Read this code text and go to next slide.g. Slide 46: 401.4.1 Intake Openings

i. This section was deleted because the requirements were re-organized and placed in the previous section.

h. Slide 47: 401.4.1 Intake Openings (Cont’d)i. This section was deleted because the

requirements were re-organized and placed in the previous section

i. Slide 48: 401 Cont’d i. This section was deleted because the

requirements were re-organized and placed in the previous section.

j. Slide 49: 401.5 Cont’d i. Here they deleted the reference to

exhaust.

k. Slide 50: 401.5 Cont’d i. The table is not shown here, only the

first line was deleted because it refers to exhaust openings.

ii. All other items in the table are for outdoor intake openings.

iii. The requirements have not changed.l. Slide 51: 403 Mechanical Ventilation

i. This section of the code is a substantial revision from the 2009 code.

k. Slide 52: Section 403i. Here is what this revision will do:ii. The airflow requirements will change. iii. The way they are calculated changes,

there are more variables introduced.iv. In some occupancies, the outdoor intake

rate will be lower as a result of this change.

v. In some occupancies, the outdoor intake rate will increase.

vi. This change is very similar to the requirements in ASHRAE 62


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vii. The requirements in our code have not substantially changed is several years.

viii. ASHRAE has been conducting studies on indoor air quality for many years.

ix. The changes reflect what they have learned and provides for a better way to determine the amount of outdoor air needed to provide for a healthy indoor environment without overly ventilating the building.

Notes Presenter slides 40 – 52:



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5. Discuss the significant changes to Definitions Chapter 2 of the 2012 NC Mechanical Code.

a. Slide 53: Breathing Zone i. We will first go over the definitions from

Chapter 2 that apply to Chapter 4.ii. The breathing zone was described in

the 2009 code in Chapter 4.iii. It has been moved to Chapter 2.iv. Read this code text.

b. Slide 54: Net Occupiable Floor Areai. Read this section and go to next slide.

c. Slide 55: Occupiable Spacei. Read this section and go to next slide

d. Slide 56: Zoneii. Read this section and go to next slide

6. Discuss the significant changes to Ventilation Chapter 4 of the 2012 NC Mechanical Code.

d. Slide 57: Ventilation Systemi. This portion of 403.1 has not changed.ii. Read this section and go to next slide

e. Slide 58: Ventilation Supply Systemi. This was deleted.ii. Part of it was moved to Chapter 2.

f. Slide 59: System Operationi. This was deleted and replaced with

new text.

g. Slide 60: Zone Outdoor Airflow i. Read this text.ii. A new term is introduced here: space

air distribution effectiveness. iii. This will be explained shortly.

h. Slide 61: Breathing Zone Outdoor Airflowi. Read this text.ii. This new equation is in two parts. iii. Let’s see what this means.

i. Slide 62: Breathing Zone Outdoor Airflow cont’d

i. Read this text.ii. Go to next slide for summary.


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j. Slide 63: Breathing Zone Outdoor Airflow cont’d

i. This equation has two components, the people outdoor air requirement and the area or building outdoor air requirement.

ii. ASHRAE studies found that the building and its contents played a significant role in the quality of the indoor air separate from the occupants and their activities.

iii. They divided the calculation into two part to account for both the people and the building. In many cases they people rate has been lowered.

k. Slide 64: Breathing Zone Outdoor Airflow cont’d

i. Zone air distribution effectiveness is a new term that accounts for the arrangement of the air distribution components, the registers, grilles, and diffusers.

ii. The zone outdoor airflow rate is a modification of the breathing zone rate to account for the effectiveness of the air distribution system.

l. Slide 65: Breathing Zone Outdoor Airflow cont’d

i. These are the significant factors that this change addresses.

ii. The ICC and ASHRAE have in recent years started working more closely together to provide a healthier and safer built environment.

iii. ASHRAE still provides standards that are more performance based while the ICC Codes are generally more prescriptive.

m. Slide 66: Zone Air Distributioni. This is the table used to account for air

distribution effectiveness. ii. Read a couple of lines from the Table.

(The class may have trouble seeing this)


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n. Slide 67: Table 403.3.1.2i. The footnotes clarify the meaning of the

terms in the Table.ii. Read the footnotes.iii. When you read footnote c, ask the

class, “ What is the height of the breathing zone?’

iv. Explain that a ceiling diffuser is a diffuser above 72” from the floor, not just in the ceiling itself.

v. So a wall diffuser at 8’ would be a ceiling diffuser.

vi. Ask where the bottom of the breathing zone is. (3”)

o. Slide 68: Table 403.3.1.2 Footnotesi. Read the text. ii. Note f addresses the type of diffusers

that would be used to provide better air distribution.

p. Slide 69: Table 403.3.1.2 Footnotesi. Footnote g. provides for no penalty

when diffusers are selected to provide better air movement and the temperature difference is low enough between the supply air and room air to provide for less turbulence at the ceiling and better air flow

q. Slide 70: 403.3 Ventilation Outdoor Airflow Rate

i. Read this text. ii. Go to next slide.

r. Slide 71: 403.3 Cont’d i. This section allows the user to select

an occupancy most similar to one in the table.

ii. The table has been revised into more section and provided more occupancies specific to different types of buildings .

s. Slide 72: 403.3 Cont’d


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i. Smoking is no longer allowed in many buildings.

ii. This section reflects that change. The ventilation rates in the Table do not take smoking into account.

iii. Where a building is expected to be occupied with the allowance of smoking this must be taken into account.

t. Slide 73: 403.3 Cont’d i. Approved statistical data can be

used for occupancies that may be significantly different from those found in the Tables.

u. Slide 74: 403 Excerpt from Tablei. This is an excerpt from the table. ii. Note that there are now 5 columns.

This section shows correctional facilities.

iii. Note that there are more occupancies than previously provided.

iv. Also note that and exhaust airflow rate column is provided where is exhaust is required.

v. Slide 75: 403 Example Calculationi. This is an example that will show the

2009 code calculations and the 2012 calculations.

ii. This is a facility that would be calculated by a registered professional, but it is important that the code official be familiar with the terms and the calculation method.

iii. These are the parameters on which the design is based:

iv. Read the slide.

w. Slide 76: 403 Example Cont’di. Read the remaining parameters.

This describes the heating and cooling system.


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x. Slide 77: 403 Calculations for 2009 i. This is the procedure for the 2009

NCMC. ii. Read through and explain as you go.iii. 20p means 20 persons, cfm/p

means cfm per person.

y. Slide 78: 403 Calculations for 2009 Cont’di. Continue to read and discuss.

z. Slide 79: 403 Calculations for 2009 Cont’di. Continue to read and discuss. I

decided that a game room was close to a day room, since there was no day room in the table.

ii. I used a lobby for the waiting area.

aa.Slide 80: 403 Calculations for 2009 Cont’di. Continue to read and discuss.

bb.Slide 81: 403 Calculations for 2009 Cont’di. Continue to read and discuss.

cc. Slide 82: 403 Summarize 2009 Calculationsi. Totals: The sum of these airflows is

shown. ii. Note the quantity and ask the class

to remember that number.iii. You can say, “about 5600”.

dd.Slide 83: 403 Calculations for 2012i. Now we will calculate the outdoor air

rate using the 2012 code.ii. Note again that there are two parts

to this initial calculation for the breathing zone airflow rate.

iii. Explain as you go.

ee.Slide 84: 403 Calculations for 2012i. Note again that there are two parts


ii. Explain as you go.

ff. Slide 85: 403 Calculations for 2012i. Note again that there are two parts



gg.Slide 86: 403 Calculations for 2012


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i. Note again that there are two parts to this initial calculation for the breathing zone airflow rate.


hh.Slide 86: 403 Calculations for 2012i. Note again that there are two parts



ii. Slide 87: 403 Calculations for 2012i. Note again that there are two parts


ii. Explain as you go.iii. For this one we actually has a

dayroom in the Table.

jj. Slide 88: 403 Calculations for 2012i. Note again that there are two parts


ii. Explain as you go.iii. There is a waiting room in the 2012

Table.

kk. Slide 89: 403 Calculations for 2012i. Note that Table 403.3 requires that

the air be exhausted from the restrooms.

ll. Slide 90: 403 Calculations for 2012i. Corridors only have the area rate

requirement.

mm. Slide 91: 403 Summarize 2012 Calculationsi. Totals for the correctional facility in

the 2012 code are 2105 of outdoor air. What was the requirement in the 2009 code? (5600).

ii. The exhausted air does have to be made up.

iii. But wait! We are not finished. iv. This is the breathing zone outdoor

airflow from Section 403.3.1.1, equation 4-1.

v. Now we must go to Section 403.3.1.2 and look at zone air distribution effectiveness.


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nn.Slide 92: 403 Zone Air Calculations 2012 i. The zone air distribution

effectiveness is determined in accordance with Table 403.3.1.2. We have said that the day room has a ceiling supply and return.

ii. Looking at the table we see that for a ceiling or floor supply of cool air, the zone air distribution effectiveness is equal to 1.0.

iii. What does footnote f say? This footnote does not apply.

iv. Now look at heating. Table 403.3.1.2, we have a ceiling supply and return of warm air in heating mode. So the effectiveness is 0.8.

v. The breathing zone rate for the day room was calculated to be 210 cfm.

vi. Using equation 4-2, the zone outdoor airflow is the breathing zone airflow divided by the zone air distribution effectiveness.

vii. In this case it is 210 cfm divided by 0.8, which gives us 263 cfm.

viii. We must use the worse case effectiveness.

oo.Slide 93: 403 Calculations 2012 Cont’di. Simply read through this and ask if

there are any questions so far.

pp.Slide 94: 403 Calculations 2012 Cont’di. How do we know that the velocity is

150 fpm at 4.5 feet above the floor?ii. From the performance data on the

diffusers.

qq.Slide 95: 403 Calculations 2012 Cont’di. This is the calculation for the waiting

room. ii. It also has a ceiling supply and

return. iii. We use the same effectiveness

factor as before.


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rr. Slide 96: 403 Calculations 2012 Cont’di. Read through this one.

ss. Slide 97: 403 Calculations 2012 Cont’di. Look at the Table for the

effectiveness of the restroom exhaust.

ii. Next to last line in the Table says “Makeup air drawn in on the opposite side of the room from the exhaust and/or return” and has an effectiveness of 0.8.

iii. Doing the math, we get 438 cfm for our zone outdoor air.

tt. Slide 98: 403 Calculations 2012 Cont’di. The same applies in the cells. ii. The zone outdoor air rate goes up to

438 cfm.

uu.Slide 99: 403 Summary of Calculations 2012 i. Here are the totals. Our total

outdoor air required is 2497. iii. This is still lower than the amount

required in the 2009 code.

vv. Slide 100: 403.3.2 Common Ventilation i. This section is replaced with several

new sections.

ww. Slide 101: 403.3.2 Common Ventilation i. We now have to use the calculated

zone outdoor airflow rates to determine the system outdoor air required.

ii. Read this section of code.iii. There are three methods based on

the type of system is used.

xx. Slide 102: 403.3.2.1 Single Zone Systems i. Read this code section.ii. For a system has only one zone,

usually only one thermostat, then the total outdoor rate for the system is the zone outdoor air rate.

iii. We are finished calculating the required outdoor air rate.


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yy. Slide 103: 403.3.2.2100% Outdoor Air Systems

i. When the system does not have return air, in other words, does not recirculate air, then the system outdoor air rate is simply the sum of all of the zone outdoor air flow rates.

ii. In this case we are finished calculating the required outdoor air rate for the system.

zz. Slide 104: 403.3.2.3 Multiple ZoneRecirculating Systems

i. This is where it gets complicated.ii. For multiple zone systems that

recirculate air we do the following:

iii. Read the code section.

iv. We have four steps to determine the final outdoor air rate required by the system.

aaa. Slide 107: 403.3.2.3.1 Primary Outdoor Air Fraction

i. We must calculate the primary outdoor air fraction.

ii. This is the zone outdoor air rate divided by the primary airflow rate.

bbb. Slide 108: 403 Primary Air Flow i. The primary airflow used in the

calculation is the lowest expected primary airflow rate when the zone is fully occupied.

ccc. Slide 109: 403.3.2.3.2 System Ventilation Efficiency

i. Next we find the system ventilation efficiency.

ii. Read the code text.iii. Note that Appendix A from the

ASHRAE Standard can be used instead of the Table.


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iv. The appendix has a calculation method that is more accurate.

ddd. Slide 110: 403.3.2.3.2 System Ventilation Efficiency Cont’d

i. First find Zp using equation 4-5, then go to the Table and select the corresponding efficiency factor.

ii. Note that the footnote allows interpolation between values.

iii. The Zp shall be the largest Zp calculated for that system.

eee. Slide 111: 403 System Calculationsi. Here is an example from our

correctional facility.ii. We had 882 cfm of outdoor air in

dining hall and 2000 cfm supply air.iii. That gives us a primary air fraction of

0.44.iv. From Table 403.3.2.3.2, our

efficiency is 0.7. v. We could interpolate and get an

efficiency of 0.71.

fff. Slide 112: 403.3.2.3.3 Uncorrected Outdoor Air Intake

i. Now we calculate an uncorrected outdoor air intake.

ii. This is simply the sum of all of the zone outdoor airflow rates that we previously calculated with one change.

ggg. Slide 113: 403 Calculationi. The change is the diversity. ii. We can apply and occupant

diversity factor to the people outdoor airflow rate.

iii. Note that this diversity factor does not apply to the area airflow rate.


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iv. Now what do they mean by system population Ps?

hhh. Slide 114: 403 Calculationi. It is the maximum number of

people expected to be in all the zones at one time.

ii. Read the text. iii. Caution: This diversity factor can

bring the outdoor airflow rate to a very low rate. There may be times when an inappropriate diversity factor may be used. If you see airflow rates that look very low, too low, check this diversity factor first.

iv. Have you heard the argument on an office building that the people in the conference room are all people who work in the building, so they will not be in their offices while the conference room is occupied?

v. This may or may not be true. In many cases, conference rooms are used for meetings with guests.

vi. I am sure you can think of times that you have been in an office building conference room when only two or three people who work in the building are in the conference room and several outside guests are there.

vii. Note that the code says the maximum number of occupants.

iii. Slide 115: 403 Diversityi. Here is an example of how

diversity can be used.ii. For our correctional facility:iii. Read the text.

jjj. Slide 116: 403 Inmatesi. The system population is ten

inmates with ten visitors, plus 30


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inmates, plus six guards plus two office workers.

kkk. Slide 117: 403 Inmates Cont’di. The sum of the populations of all

the zones is the 80 persons in the cells, the 70 people in the dining hall, the 6 guards

lll. Slide 117: 403 Inmates Cont’di. The sum of the populations of all

the zones is the 80 persons in the cells, the 70 people in the dining hall, the 6 guard

mmm. Slide 118: 403 Summaryi. The two office workers, the 30

people in the day room and the 20 people in the waiting room.

nnn. Slide 119: 403 Summary Cont’d i. That gives us a total population of

208

ooo. Slide 120: 403 Summary Cont’d i. We divide the expected system

population by the sum of the zone populations and get a diversity factor of 0.28.

ppp. Slide 121: 403 Summary cont’d i. Now let’s get a look at a different

scenario.ii. Read text.

qqq. Slide 122: 403 Zone Populations i. The sum of the zone populations

does not change.ii. This time we get a diversity factor

of 0.41.iii. What does that do to our outdoor

airflow rate?

rrr. Slide 123: 403 Outdoor Airflow Ratei. For the first example, we have

reduced our outdoor airflow rate from 2015 to 1104.


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ii. For the second example, we have reduced our outdoor airflow rate to 1269.

iii. Diversity can make quite a difference.

sss. Slide 124: 403.3.2.3.4 Outdoor Air Intake Flow Rate

i. Now we can apply system efficiency.

ttt. Slide 125: 403.3.2.3.2 Outdoor Air Intake Flow Rate

i. We calculated a primary air fraction of 0.44.

ii. The first value of Vot is with a diversity of 0.28.

iii. The second value of Vot is with a diversity of 0.41

uuu. Slide 126: 403.4 Exhaust Ventilationi. This is the section on make-up air

for the exhaust air.ii. Note that makeup air can be from

other zones, except where limited by Section 403.2.

iii. Read section

vvv. Slide 127: 403.6 Variable Air Volume System Control

i. Read Section.ii. The control system must be able

to regulate the outdoor air throughout the system to provide outdoor air to each zone as part of the supply air.

www. Slide 128: 403.7 Balancingi. The system must be balanced to

achieve the minimum ventilation airflow rate.

xxx. Slide 129: 403 Example 2 i. This example is similar to the

example in the 2009 International Mechanical Code Commentary. We will do this one together.

ii. If you have a calculator, or a calculator feature on your cell phone, please follow along.


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iii. It will mean more to you if you go through the calculations yourself.

iv. Note to instructor to go through this slowly to allow time for them to perform the calculations.

v. You may obtain a spreadsheet from Janie Sutton at DOI for the purpose of this exercise by emailing her at [email protected].

vi. The spreadsheet has numbered columns and the supply airflow rates and zone areas are already filled in.

vii. Try to make sure the class understands at least the first part through section 403.3.2.2.

viii. Encourage Level II and Level III Mechanical Inspectors to study the entire section.

ix. If you are using the spreadsheet, note that the areas are already listed on the spreadsheet.

yyy. Slide 130: 403 Example 2 cont’dx. Read this information and

proceed to next slide,

zzz. Slide 131: 403 Example 2 cont’di. If you are using the spreadsheet,

note that these values are entered on the spreadsheet for the class.

aaaa. Slide 132: 403 Example 2 Step 1 ii. Step 1. First we will determine

the occupant loads for all zones and enter them on our spreadsheet.

iii. For the conference room, from Table 403.3 under the Offices section, a conference room has


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an occupant density of 50 people per 1000 square feet.

iv. Enter the number 50 in column 4 of the spreadsheet in the conference room row.

v. The area is already entered, so divide 50 by 1000 and multiply by 280.

vi. Enter 14 under column 5.

bbbb. Slide 133: 403 Example 2 Step 1 cont’d

i. Do the same for the data center. Find data center in the Table and enter the occupant density under column 4. Do the calculation. Did you get 7.2?

ii. What about the decimal places?iii. Do we carry them or round up or

down?iv. It doesn’t really matter that much.

When I am using a spreadsheet I usually leave them in until the end. It will not make much difference at all in the airflow rate.

cccc. Slide 134: 403 Example 2 Step 1 cont’d i. Do the same procedure for the

reception area. Enter 30 people for the occupant density, divide by 1000 and multiply by the area.

ii. Did you get 3.6? Any questions so far?

iii. (If so, repeat the question for all to hear and explain. Go back if necessary.)

dddd. Slide 135: 403 Example 2 Step 1 cont’d i. Proceed the same way for the

office space. ii. Note that the density is 5 for the

2012 code and was 7 for the 2009 code.

eeee. Slide 136:403 Example 2 Step 2 i. Enter the people OA rate in

column 3. 5 cfm for the conference room. (Have them


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look it up in the Table and tell you what it is.)

ii. Note that for this building all of the area airflow rates are the same. 0.06 is entered in column 6.

ffff. Slide 137:403 Example 2 Step 2 cont’di. This is the calculation for the

conference room. ii. The breathing zone airflow rates

are broken out separately. When density is applied, they must be separated because the density factor is not applied to the area rate.

iii. In column 7 enter the total of 5 cfm/p x 14p = 70.

iv. Do the calculation for the area rate and enter it: 16.8.

v. In column 9 enter the Total breathing zone airflow rate of 86.8.

gggg. Slide 138:403 Example 2 Step 2 cont’di. Do the same for the data center.

By now, someone might recognize the people outdoor air rate is the same for all occupancies in this building.

ii. In column 3, enter 5 cfm, column 7 enter 36.

iii. In column 8, enter 7.2, and column 9 enter 43.2.

hhhh. Slide 139:403 Example 2 Step 2 cont’di. In column 3, enter 5 cfm, column

7 enter 18.ii. In column 8, enter 7.2, and

column 9 enter 25.2.

iiii. Slide 140:403 Example 2 Step 2 cont’di. In column 3, enter 5 cfm, column

7 enter 137.ii. In column 8, enter 328.8, and

column 9 enter 465.8.

jjjj. Slide 141:403 Example 2 Step 3


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i. Determine the efficiency for each zone, then the outdoor airflow rate for each zone.

kkkk. Slide 142:403 Example 2 Step 3 cont’di. The default efficiency in the Table

is 1. This is column 10.ii. (Read the text on the slide.)iii. Enter the efficiency in column 10. iv. Remember we must use worse

case.llll. Slide 143:403 Example 2 Step 3 cont’d

i. Multiply column 9 by column 10 and enter result in column 11.

ii. Continue for all four zones.

iii. Instructor: Check with class to see if they are understanding.

iv. Ask as you go what the answers are. If they don’t understand, go back and do it again.

mmmm. Slide 144:403 Example 2 Step 3 cont’di. Enter the rest of the calculated

values on the spreadsheet.

nnnn. Slide 145:403 Example 2 Step 4i. Now we must determine values for

the primary air fraction. ii. This is the zone outdoor air value

(column 11) divided by the primary air value (column 12).

iii. This value goes in column 13.

oooo. Slide 146:403 Example 2 Step 4 cont’di. For the conference room, column 11

has 108.5 and column 12 has 440 cfm.

ii. When divided, you get? iii. That value goes in column 15.

pppp. Slide 147:403 Example 2 Step 4 cont’di. Do the same thing for the three

remaining zones.

qqqq. Slide 148:403 Example 2 Step 5i. Now look at the values in column

13 (Zp). What is the largest number?


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ii. That is the number used to determine the system efficiency. Using that number, 0.25, go to the Table.

iii. The system efficiency is 0.9.iv. Enter 0.9 in column 14 on the last

line, the line marked “Totals”.

rrrr. Slide 149:403 Example 2 Step 6

i. On this example we are going to use a diversity of 1.

ii. A diversity of 1 is always allowed because it will not lower the outdoor airflow rate.

iii. The diversity is entered in column 15 on the last line where the totals are.

iv. If diversity was used, you would multiply it by the total in column 1 and add that value to the total in column 8. This number would go in column 18.

v. Since our diversity is one, we can simply use the total in column 9, last line.

ssss. Slide 150:403 Example 2 Step 6 cont’di. Here is what is happening. ii. Since all the occupant densities

are the same, and all the area rates are the same,

iii. we can multiply the occupant density by the total of all zone populations (it is broken out by zones here) and

iv. multiply the area rate by the total building area to get the uncorrected outdoor airflow rate.

v. This number goes into column 18.

tttt. Slide 151:403 Example 2 Step 7i. Now we apply the system

efficiency to the uncorrected outdoor airflow rate to get the required system outdoor airflow rate.


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ii. In the last row, “Totals”, place the result in column 17.

iii. You will be dividing column 16 by column 14.



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End of Presenter slides 57 – 152:

7. Discuss the significant changes to Ventilation Chapter 5 Exhaust Systems of the 2012 NC Mechanical Code.


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a. Slide 153: Chapter 5 Exhaust Systemsi. This was mentioned at the

beginning of Chapter 4. In Chapter 4, we saw where the exhaust requirements were removed.

ii. Now we will see where ventilation requirements are removed from Chapter 5, and requirements for exhaust that were in Chapter 4 are moved to Chapter 5.

b. Slide 154: Chapter 5 Exhaust Systemsi. Read slide and go to next slide.

c. Slide 155: 501.2.1 Location of Exhaust Outletsi. 1 and 2 are other than

environmental air.ii. Read the new item. iii. Comment on the word all and the

removal of the word duct. This item applies to all environmental air exhaust, whether ducted or not.

d. Slide 156: 501.2.1 Location of Exhaust Outlets Cont’d.

i. Simply read this section and go to next slide.

e. Slide 157: 501.2.1 Location of Exhaust Outlets Cont’d.

i. Simply read this section and go to next slide.

f. Slide 158: 501.2.1.1 Exhaust Dischargei. Read this section and discuss.

What do they mean by directed?ii. Does this mean that an exhaust

fan cannot be placed above a walkway?

iii. (No. If the exhaust is high enough to keep the airflow from passing onto walkers and the airflow is not directed downward,


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the intent of this section has been met.)

g. Slide 159: 501.2.2 Exhaust Opening Protection

i. Read this slide and move to next slide.

h. Slide 160: 501.2.2 Exhaust Opening Protectioncont’d.

i. This section covers the requirement that was in the Table in Chapter 4.

ii. Since there is only one requirement for protecting exhaust openings, it was entered in paragraph form.

i. Slide 161: 501.3 Exhaust Opening Protection cont’d.

i. This is an introduction to the next slide.

j. Slide 162: 501.3 Pressure Equalization i. The exception is intended to not

require makeup air for exhaust systems in residential occupancies unless specified elsewhere in the code.

ii. R-2 is non-transient multi-family housing such as apartment buildings, dormitories, and boarding houses.

iii. R-3 is institutional residential, where the occupants are non-transient, such as day care for adults or children, and 6 occupants or less.

iv. The code change allows dwelling units in R-2 occupancies to not have neutral or negative pressure maintained.

v. The exception if for residential: one and two-family dwellings and townhouses.

k. Slide 163: 504.5 Makeup Air


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i. This change removes the requirement for makeup air for clothes dryers exhausting more than 200 cfm.

ii. It simply states that make-up air be provided by an opening or other means.

l. Slide 164: Section 504 Discussion i. Read and discuss this slide.ii. Discuss effective area.

m. Slide 165: 504.6 Domestic Clothes Dryer Ducts i. Read or paraphrase this slide

and move to the next.

n. Slide 166: 504.6 Domestic Clothes Dryer Ducts i. You do not need to read the

deleted text. ii. Inform the class that this section

has changed.

o. Slide 167: 504.6 Domestic Clothes Dryer Ducts cont’d.

i. This has been re-written.

p. Slide 168: 504.6 Domestic Clothes Dryer Ducts cont’d.

i. The exception has not been deleted. It simply has been moved.

ii. Note that in the current code, it reads 200 square feet, this is an error.

iii. It should read 200 square inches.

q. Slide 169: Section 504.6 Deletionsi. The maximum length requirement

and how it is determined have changed.

r. Slide 170: 504.6.1 Deletions cont’d.i. This has been re-organized.

s. Slide 171: 504.6.2 Deletions cont’di. This has been changed.

t. Slide 172: Section 504 New


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i. New Code. We now have seven sub-sections describing the requirements for domestic clothes dryer exhaust.

ii. Number one: Read 504.6.1. Note that the duct shall be constructed of metal.

iii. The question came up in some classes as to whether you can use pvc duct for clothes dryer exhaust under the slab.

iv. This section makes it clear that pvc is not allowed.

u. Slide 173: Section 504 New i. Ask the class why the duct shall

extend into the fitting in the direction of airflow. Why can’t they use screws?

ii. The inside of the duct must be smooth with no ridges or protrusions of any kind to that the clothes dryer lint will not catch and block the duct.

v. Slide 174: Section 504 New Amendmenti. Here is the North Carolina

amendment exception. The 200 square feet was changed to 200 square inches.

w. Slide 175: 504.6.3 Transistion Ductsi. Read this slide and go to the next

slide.

x. Slide 176: Section 504 New Amendmentsi. This section describes the two

methods of determining the maximum allowable duct length.

ii. First listed is the specified length.

iii. The maximum length has been changed to 35 feet. The previous IMC had 25 feet, North Carolina amendment changed it to 45 feet.


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The BCC Mechanical Ad Hoc Committee decided to stay with the ICC change.

iv. We now have a table defining the equivalent length of the fittings.

y. Slide 177: Table 504.6.4.1i. Read some of this table to the

class. ii. Note that there are several sizes

of fittings. iii. For a single dryer, section

504.6.1 requires the duct to be 4” in diameter.

z. Slide 178: Table 504.6.4.2 Mfgr’s Instructionsi. This is the second method.

The clothes dryer manufacturer’s installation instructions may be used instead of the equivalent length method.

ii. If you cannot route the duct to the exterior in the specified maximum length, what alternatives do you have?

iii. Relocate the clothes dryer, or provide a condensing dryer that does not require an exhaust.

iv. Booster fans are not allowed because there is no fan available that is listed for such use.

v. To our knowledge there is not yet a listing for a clothes dryer duct booster fan.

aa.Slide 179: 504.6.5 Length Identificationi. This section was amended by the

North Carolina Building Code Council to require equivalent length label or tag in any case, whether concealed within construction or not.

ii. This is important information for the owner or installer to know.

iii. From NFPA statistics on house fires:Clothes dryers accounted for the largest share of appliance


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and tool fires between 1994-1998.

iv. There were 14,300 clothes dryer fires in U.S. homes in 1998, resulting in 19 deaths, 312 injuries and $67.7 million in direct property damage.

v. The leading cause of home clothes dryer fires was lack of maintenance (30%), followed by unidentified or unknown-type mechanical failure (11%) and part failure, leak or break (10%).

vi. Clothing (not on a person) was the most common source of ignition in home clothes dryer fires, followed by dust, fiber or lint.

bb. Slide 180: Table 504.6.6 Exhaust Duct Req’di. If there is no exhaust duct system

installed, the condensing clothes dryer shall be installed prior to occupancy!

ii. No dryer = no C.O.iii. This section is not intended to

require a tag or label stating that there is no clothes dryer exhaust system.

iv. Those little boxes you see at the “big box” store that sit on the floor of the laundry room and collect clothes dryer lint are not an acceptable alternate to an exhaust system ducted to the outdoors.

cc. Slide 181: Table 504.6.6 Exhaust Duct Req’di. The Table has 4” mitered, and 6”

smooth. ii. When the equivalent length

information is not on the Table, you can use the tables supplied by SMACNA or ASHRAE for that fitting.

iii. North Carolina Building Code Committee had decided that 25 feet was to restrictive, when ICC changed it to 35 feet, the


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Committee decided to not amend it to 45 feet.

dd. Slide 182: Section 504.8 New i. This is the first time that a

common shaft for multiple clothes dryers is addressed.

ii. This set of requirements are based on designs that have been used successfully in several jurisdictions in the U.S.

iii. The provisions address issues to make sure the velocity in the exhaust system is maintained, moisture is controlled so that building components will not be damaged, and lint in the system does not build up to where it would create a hazard.

ee. Slide 183: 504.8 New requirementsi. Read this slide and go to next

one.

ff. Slide 184: 504.8 New requirements # 1& 2i. Read this slide and go to next

one.

gg. Slide 185: 504.8 New requirements #3i. Read this slide and go to next

one.

hh. Slide 186: 504.8 New requirements # 4-7i. Read this slide and go to next

one.

ii. Slide 187: 504.8 New requirements # 8-11i. Read this slide and go to next

one.

jj. Slide 188: 504.8 Diagrami. This is a diagram of the

requirements of this section. ii. Point out each item on the

diagram.iii. The next slides review these

requirements in more detail.

kk. Slide 189: 504.8 # 2i. #2. Dampers shall be prohibited

in the exhaust duct. Penetrations


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of the shaft and ductwork shall be protected in accordance with Section 607.5.5, Exception 2.

kk. Slide 190: 504.8 # 3, # 5ii. #3. Rigid metal ductwork shall be

installed within the shaft to convey the exhaust.

iii. The ductwork shall be constructed of sheet steel having a minimum thickness of 0.0187 inch (0.4712 mm) (No. 26 gage) and in accordance with SMACNA Duct Construction Standards.

iv. The exhaust fan motor design shall be in accordance with Section 503.2.

v. #6. 503.2 Fans. Parts of fans in contact with explosive or flammable vapors, fumes or dusts shall be of nonferrous or non-sparking materials, or their casing shall be lined or constructed of such material. . . . Fans in systems-handling materials that are capable of clogging the blades, and fans in buffing or woodworking exhaust systems, shall be of the radial-blade or tube-axial type.

vi. Go back to the diagram and ask for comments. Ask the class about the cleanout at the bottom. (It shall be a fire door since it is in a fire rated shaft.)

vii. There are fan manufacturers who are selling pressure control systems for this application and providing instruction on this application.

viii. All of the provisions of this code may or may not be covered in those instructions.

ix. Whether they are or not, these provisions shall be met.


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x. The pressure control system goes above code and is not required.

ll. Slide 191: 505.2 Makeup Air Requiredi. Read the code text and go to next

slide for explanation.

mm. Slide 192: 505.2 Makeup Air Requiredi. Domestic kitchens are becoming

more like commercial kitchens, both aesthetically and functionally.

ii. Much higher capacity appliances are being installed and much higher capacity range hoods are installed as a result.

iii. This can create an inadequate amount of makeup air for all of the exhaust from the dwelling.

iv. Indoor negative pressures can cause problems with the operation of the appliances, the heating and cooling system, and if present, the fireplace.

v. This section is designed to mitigate some of those problems.

vi. The means of closure is to prevent excessive energy loss when the unit is not operating.

vii. When the homeowner is operating the exhaust fan the makeup air system must be operating as well.

nn. Slide 193: 506.3.8 Grease Duct Cleanoutsi. The requirement for doors

designed to be opened without a tool has been removed.

ii. Go to next slide.

oo. Slide 194: 506.3.8 Grease Ducts cont’di. Discuss this one.ii. Ask if they have seen these

doors where the “wing nuts” will not create a tight closure.


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iii. After a time, they are difficult to tighten and the duct starts to leak.

pp. Slide 195: Section 506.3.6 and 506.3.10i. The primary reason for this

change was to consolidate and simplify the grease duct clearance requirements with the enclosure requirements.

ii. This reorganization separates the three options into three separate sections.

qq. Slide 196: Section 506.3.6 and 506.3.10 cont’di. 506.3.6 now talks about grease

ducts only where enclosures are not required and section 506.3.10 talks about clearances where enclosures are required.

ii. Read the text (mostly for review), go to next slide.

rr. Slide 197: Section 506.3.6 Exceptionsi. The exceptions are for materials

and equipment that, because of their listing, already have an established clearance to combustibles in their installation instructions.

ii. 304.1 is the section for listing, labeling and manufacturer’s instructions.

ss. Slide 198: Section 506.3.10 Re-writteni. This section has been re-written.

tt. Slide 199: Section 506.3.10 Re-writteni. This section has been re-written.

uu. Slide 200: Section 506.3.10 Re-writteni. This section has been re-written.

vv. Slide 203: Section 506.3.10 Re-writteni. Now the new code language. ii. Read this slide and go to next

slide.

ww. Slide 204: Section 506 Exception


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i. Note that there are three methods described in the next three sections.

ii. Read the slide and go to next slide.

xx. Slide 205: Section 506.3.10.1 Shaft Enclosurei. First: The Shaft Enclosure: ii. This includes both horizontal and

vertical runs of duct. iii. The enclosure must originate in

the room containing the hood and must extend to where the duct discharges to the outdoors.

yy. Slide 206: Section 506.3.10.2 Field –applied Grease Duct Enclosure

i. Method 2: Field- applied enclosure:

ii. More commonly known as “fire wrap”.

iii. It must meet ASTM E 2336.

yy. Slide 207: Section 506.3.10.2 cont’di. Read slide and go to next.

zz. Slide 208: Section 506.3.10.3 Factory-built Grease Duct Assemblies

i. Method 3: In order to comply with UL 2221 the enclosure must first pass the tests for UL 1978, and then has added insulation to comply with UL2221.

ii. Some of these systems have 0 clearance to combustibles.

iii. These systems are often used where clearance is a problem or where “fire wrap” is likely to get damaged.

aaa. Slide 209: Section 506 Summaryi. Summary, move to next slide.

bbb. Slide 210: Section 506 Summary cont’d


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i. There are several new requirements for Type II kitchen hood exhaust.

ccc. Slide 211.0: Section 506 Deletionsi. This section has been

re-arranged and expanded.

ddd. Slide 212: Section 506.4.1 Ductsi. This portion of 506.4 has not

changed, it is just moved.ii. Read section and go to next

slide.

eee. Slide 213 : Section 506.4.2 Type11 Ductsi. These are the new requirements

for termination of exhaust outlets serving Type II hoods.

ii. Read slide and go to next one.

fff. Slide 214: Section 506.4.2 cont’di. Read slideii. Go to next slide for illustration.

ggg. Slide 215: Section 506.4.2 cont’di. Go over the requirements in the

illustration and ask for questions.ii. Note the 10’ above grade. iii. This coordinates with Section

501.2.1.1, requiring that exhaust not be directed onto walkways.

iv. The 30” minimum to exterior walls is to prevent damage to wall from steam or heat.

hhh. Slide 216: Section 506.4.2 cont’di. Read and discuss if you want.

iii. Slide 217: Section 507i. Section 507 is on commercial

cooking appliances.ii. Read and go to next slide.

jjj. Slide 218: Section 507.2.1 Type 1 Hoods


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i. Read the new code text. ii. Note the NC amendment.iii. Note that there are no exceptions

for heavy-duty and extra-heavy-duty cooking appliances.

kkk. Slide 219: Section 507.2.2 Type II Hoodsi. Read text.ii. Note that it states “except where

the heat and moisture loads from such appliances are incorporated into the HVAC system design or into the design of a separate removal system,”

iii. Move to next slide.

lll. Slide 220: Section 507.2.2 cont’di. These exceptions have not

changed. ii. Note that the new code text

covers exception 2. iii. These exceptions were removed

from the IMC, but were included by North Carolina Amendment.

mmm. Slide 221: Section 507.2.2 cont’di. So, with the new code text, for a

medium-duty or light-duty appliance that does not produce grease or smoke, the Type II hood is required unless the appliance has its own exhaust system or the HVAC system is designed to handle the additional load.

nnn. Slide 222: Section 507.2.2 cont’di. This is a summary of how to

determine whether a hood is required.

ii. For gas-fired appliances a system must be in place to handle the products of combustion, whether it is a hood, or a separate exhaust system.

ooo. Slide 223: Section 507.2.3 Domestic cooking appliances used for commercial purposes.


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i. This section was changed by North Carolina Amendment.

ii. The four-burner requirement is gone.

ppp. Slide 224: Section 507.2.3 cont’d i. The middle burner on some of

these 5 burner ranges is for warming and holding only and is design to lower maximum temperatures.

ii. We are seeing these being installed in churches and day care centers.

iii. The key is whether it is being used for commercial purposes on a regular basis.

iv. In other words if they are preparing food to be sold to the general public, a hood would be required if required by Section 507.

v. Churches generally prepare food only for their congregations.



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End of Presenter slides 153 – 224:

8. Discuss the significant changes to Duct Systems Chapter 6 of the 2012 NC Mechanical Code.


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a. Slide 225: Section 601.2 Air movements i. The intent of this section remains

the same. ii. An exception was added for

clarity.

b. Slide 226: Section 601.2 cont’d i. Ask if they remember what the

first 3 exceptions are. (dwelling units, tenant spaces of 1000 square feet or less, and use of corridor for makeup air for rooms open directly onto the corridor)

ii. It was never the intent of this section to prevent the use of air supplied to the corridor to be used as makeup air. This is a clarification.

iii. It is not the intent of this section to prevent a corridor from being conditioned.

iv. Supply and return air is allowed in the corridor, the corridor cannot be used as a supply or return duct.

v. Plan reviewers may often see air supplied to a long corridor with only a return grille at the end of the corridor.

vi. This arrangement uses the corridor for return air duct.

vii. If return grilles are placed in several locations in the corridor, then in a fire scenario, smoke will not likely travel all the way down the corridor.

c. Slide 227: Section 601.4 Contamination Prevention

i. Read this slide, excluding the deleted code text.

ii. The exhaust system for environmental air would fall into this category.

d. Slide 228: Section 601.4 Contamination Prevention cont’d


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i. A “vent” in the Mechanical Code is a conduit for conveying combustion air.

ii. The use of the word vent is not intended for plumbing vents.

e. Slide 229: Section 601.4 Contamination Prevention

i. Read slide and go to next slide for comment.

f. Slide 230: Section 602.2.1 Materials within plenums

i. This section covers materials within plenums, not the plenum construction itself.

ii. This requirement is regardless of whether the plenum is constructed of combustible materials.

iii. Section 602.2 covers the construction of the plenum enclosure.

iv. The code permits limited types of combustible materials for mechanical, electrical, fire protection, communication and plumbing systems.

g. Slide 231: Section 602.2.1 Exceptions i. Sections 603 and 604 cover the

burn and smoke ratings for ducts, connectors, sealants, and coverings.

ii. The code exempts one and two family dwellings.

iii. A dwelling is a building that contains not more than two dwelling units.

iv. If a building has more than two attached dwelling units, materials in plenums must comply with this section, except for within the dwelling units as described in exception 6.

h. Slide 232: Section 602.2.1 Exceptions cont’d


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i. The North Carolina Amendment allows materials in furnace rooms and air handler rooms to be combustible as long the room is inside a dwelling unit.

ii. Explain the difference between plenums inside apartment units and plenums in other areas of an apartment building.

i. Slide 233: Section 602.2.1.4 Deletions i. This section has been re-written,

with two subsections.

j. Slide 234: Section 602 Summary i. Read the code text.ii. This section now allows electrical

equipment in metal enclosures to be located in a plenum because they are non-combustible.

iii. Equipment that has combustible enclosures must meet the requirements of UL 2043.

k. Slide 235: Section 603.4.1 Minimum fasteners i. Screws that are placed in close

proximity to each other are not acceptable.

ii. Even where the duct is against a wall or ceiling so that the screws cannot be placed equidistant around the duct, they must be placed so that the connection will not flex, sag, or move like a hinged joint.

l. Slide 236: Section 603.4.1 cont’d i. An example of 3 screws placed

equidistant apart. ii. Go to next slide

m. Slide 237: Section 603.4.1 cont’d i. Read or paraphrase this

information. ii. Ask, what if it is a 12” duct?iii. What if it is a 5” duct? iv. Answer: 3 screws.


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n. Slide 238: Section 603.7 Rigid duct penetrations

i. This portion of section 603.7 has not changed.

o. Slide 239: Section 603.7 cont’d i. North Carolina Ad Hoc

Committee added “or other approved material”.

ii. UL testing found that duct board could withstand fire tests as long as 26 gauge duct could.

iii. This only applies to a private garage.

iv. The duct shall be galvanized sheet metal or other approved material as it goes through the wall.

v. It should not transition to flex duct until after it passes through the wall separating the dwelling unit from the garage.

p. Slide 240: Section 603.7 cont’d i. This section does not prohibit

duct openings in the garage if the system serves only the garage and does not pass through any walls, floors or ceiling of the garage that connect to the dwelling unit.

q. Slide 241: Section 603.18 Return-air intake i. The ad hoc committee decided

that this section fit better in Chapter 6, duct systems than it did in Chapter 9 for specific appliances.

ii. Section 603.18 is for location, number and size of return air intakes and was moved unchanged.


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r. Slide 242: Section 603.19 Under floor plenumsi. This is a carryover from previous

codes. ii. The Committee decided it was

important to keep this in the codes for maintenance and repair of this type of system.

s. Slide 243: Section 603.19.2 Materialsi. Read text and move to next slide.

t. Slide 244: Section 603.19.3 Furnace connections

i. Read text and move to next slide.

u. Slide 245: Section 603.19.3 Furnace connections cont’d

i. Read text and move to next slide.

v. Slide 246: Section 603.19.4 Accessi. Read text and move to next slide.

w. Slide 247: Section 603.19.5 Furnace controlsi. Read text and move to next slide.

x. Slide 248: Section 603.19 Discussioni. This illustration is from an old

residential code (CABO). ii. Note that the beginning sentence

of this section prohibits under floor plenums in new construction.

y. Slide 249: Section 603.19 Discussion cont’di. A heat pump is a furnace.

z. Slide 250: Section 603 Discussion i. When this part of the code is applied

for existing construction only, if the plenum is being repaired and existing plumbing cleanouts are present, they do not have to be removed.

ii. New plumbing cleanouts would not be allowed to be installed in an existing under-floor plenum.

aa.Slide 251: 604.3 Coverings and Linings


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i. This section covers the linings and covering material for duct insulation.

ii. UL 723 and ASTM E 84 are virtually identical.

iii. The UL standard was added for clarity.

bb.Slide 252: 604.7 Identification i. Spray foam insulation for ductwork is

an acceptable means for insulating ductwork and provides additional sealing of the duct.

ii. Note that spf over ductwork in an attic or crawlspace must be covered with a thermal or ignition barrier depending on the accessibility and intended use of the attic or crawlspace.

cc. Slide 253: 604.7 Identification (Clarification )i. Richard S. Duncan, Ph.D., P.E.

Technical Director of the Spray Polyurethane Foam Alliance in Fairfax, Virginia says this about aged R-value.

ii. “Age R-value is the R-value measured for a fixed aging period and temperature condition after the product is sprayed.

iii. The accepted conditions for R-value aging are 180 days at 73F or 90 days at 140F.

iv. This aging is needed because insulating blowing agents in the cells near the surface of the foam will off-gas and slightly lower the thermal performance to a terminal value over this period.

v. Aged R-value for foam plastics are required by the FTC for residential insulations, and should be the only R-values reported by the supplier or manufacturer.


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vi. Any foam possessing a valid ICC ES Report or ESR will report the aged R-value.”

dd.Slide 254: 606.4.1 Supervisioni. The 2009 code text gave the

impression that a fire alarm system was required.

ii. The change is to clarify this section. Go to next slide for comment.

ee.Slide 255: 606.4.1 Supervision cont’di. Discuss and go to next slide.

ff. Slide 256: Section 607 Discussioni. Read slide and go to next slide.

gg.Slide 257: Section 607.5 Where requiredi. A ceiling radiation damper has a

different testing method from fire and smoke dampers.

ii. The ICC does not consider a radiation damper to be a fire damper.

hh.Slide 258: Section 607 Discussioni. Read and move to next slide.

ii. Slide 259: Section 607.5.5 Shaft enclosuresi. Fire and smoke dampers are

prohibited in kitchen exhaust systems and in dryer exhaust systems.

jj. Slide 260: 607.5.5 Shaft enclosures cont’di. Read or paraphrase and move to

next slide.

kk. Slide 261: 607.5.5.1 Enclosure at the bottomi. Read and go to next slide.

ll. Slide 262: Chapter 6 Discussioni. Read and comment. ii. One comment might be, “If the

lowest floor is one hour rated, and the shaft is two hour rated, what is the required rating at the bottom of the shaft?

iii. Two hours.”


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kk. Slide 263: Chapter 6 Discussion cont’di. This is an illustration of the shaft

enclosed at the bottom. ii. The yellow and green at the shaft

penetrations are fire and smoke dampers.

ll. Slide 264: Chapter 6 Discussion cont’di. Read this and move to next slide.

mm. Slide 265: Chapter 6 Discussion cont’di. This is a mechanical room for the air

handling unit. ii. Since the shaft is providing routing

for the duct system from the air handler, its use is related to the use of the room.

iii. Note that the room shall be enclosed with fire rating equal to the shaft.

iv. The adjoining room could be any room and is shown here as rated on all sides.

v. Only the room adjoining the shaft needs to be rated.

nn. Slide 266: Chapter 6 Discussion cont’di. Read this slide and go to next slide for

comment.

oo. Slide 267: Chapter 6 Discussion cont’di. This is an example of the third method.

The requirement for a smoke damper in Section 716.5.3 must also be met unless it meets one of the exemptions.

pp. Slide 268: Section 607.5.6 Exterior Wallsi. NCBC Section 705.10 requires that

penetrations in fire rated exterior walls be protected.

ii. Table 705.8 of the NCBC gives the maximum allowable area of openings based on fire separation distance.

iii. Note that exhaust outlets that cannot have fire dampers, such as kitchen exhaust and dryer vents cannot be located in walls that are required to be protected.


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qq. Slide 269: 607.5.6 Exterior Walls cont’di. Read or paraphrase.

rr. Slide 270: 607.5.6 Exterior Walls cont’di. In other words, if a duct or vent that

is prohibited from having fire dampers installed in an exterior wall, it must be in a non-rated wall.

ss. Slide 271: 607.5.6 Exterior Walls cont’di. Read and move on.

tt. Slide 272: 607.5.7 Smoke partitionsi. Read slide and go on to next.

uu.Slide 273: 607.5.7 Smoke partitions cont’di. Illustration of smoke partition with air

transfer opening. ii. The smoke damper is required in an

air transfer opening, but a duct penetration is required to be installed “to resist the passage of smoke”.

vv. Slide 274: Section 607 Discussionsi. This is also covered in the North

Carolina Building Code.


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Notes Presenter slides 225 - 274:

End of Presenter slides 224 - 274:


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9. Discuss the significant changes to Combustion Air Chapter 7 of the 2012 NC Mechanical Code.

a. Slide 275: Chapter 7 Combustion Airi. Read this introduction and go to next

slide.

b. Slide 276: Section 701.1 Scopei. Read the text and go to next slide for

explanation of the change.

c. Slide 277: Chapter 7 Discussioni. Natural gas appliances have different

operating characteristics from solid and liquid fuel burning appliances. Combustion air requirements should be specific to the fuel type.

ii. For Fuel Gas appliances, the requirements are found in the Fuel Gas Code.

iii. For oil burning equipment, the requirements are found in NFPA 31.

iv. For solid fuel burning appliances, the requirements are found in the appliance manufacturer’s installation instructions.


End of Presenter slides 275 - 277:Significant Changes to the 2012 NC Mechanical Code Lesson Plan

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10.Discuss the significant changes to Chimneys and Vents Chapter 8 of the 2012 NC Mechanical Code.

a. Slide 278: Chapter 8 Chimneys & Vents Section 801.18.4 Clearances

i. Read slide and go to next one.d. Slide 279: Chapter 8 Chimneys & Vents

Section 801.18.4 Clearancesi. The Exception is changed.

e. Slide 280: Chapter 8 Chimneys & Vents Section 801.18.4 Clearances

i. Read code text. ii. The exception now makes it clear

that the clearances are based on the chimney liner listing and manufacturer’s instructions.

iii. Previously it was implied that no clearance was required.

iv. Some of these systems require clearances and some have no required clearance to combustibles.

f. Slide 281: Section 801 Discussion Section 801.18.4 Clearances

i. Read or paraphrase.g. Slide 282: Section 801.18.4.1 Fireblocking

i. This was in moved to its own section so that 801.18.4 deals with clearances, and 801.14.1 deals with fireblocking.

h. Slide 283: 801.20 Plastic Vent Joints i. Note that the solvent cement joints

requirement is deleted. i. Slide 284: Section 801 Discussion

i. Go over this slide by paraphrasing.



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11. Discuss the significant changes to Specific Appliances, Fireplaces, Solid Fuel-Burning Equipment Chapter 9 of the 2012 NC Mechanical Code.

a. Slide 285: Chapter 9 Specific Appliances, Fireplaces, and Solid

Fuel- Burning Equipment Section 918.6

Prohibited Sources i. Read this code text. ii. Go to next slide.

b. Slide 286: Chapter 9 Section 918.6 Prohibited Sources

i. Read this code text and explain that

this if for where kitchens are open to other areas.

ii. It is difficult to determine where the kitchen ends and the adjoining area starts.

iii. The intent is to keep kitchen odors and vapors from getting into the HVAC system and to prevent the disruption of the hood performance.


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c. Slide 287: 918.6 Prohibited Sources cont’d.

i. Taking return air from conditioned crawl spaces is acceptable.

d. Slide 288: 918.6 Prohibited Sources cont’d.

i. This would also apply to a fireplace insert or fireplace stove.

e. Slide 289: 918.6 Prohibited Sources cont’d.

i. Read or paraphrase these comments. ii. Go to next slide.

f. Slide 290: 918.6 Prohibited Sources cont’d

i. This section only addresses outdoor (ventilation) or return air for a forced-air heating system.

ii. The change in 7.4 was for clarification. iii. The wording in the 2009 NCMC was

confusing.

g. Slide 291: Section 927 Heat Recovery Ventilators

i. Heat recovery units are becoming more popular, even in residential construction, so they were added to the code.

h. Slide 292: Section 927 Heat Recovery Ventilators cont’d

i. Heat recovery units are now included as listed and labeled appliances.


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End of Presenter slides 285 - 292:12. Discuss the significant changes to Hydronic Piping

Chapter 10 of the 2012 NC Mechanical Code.

i. Slide 293: Chapter 10 Boilers,Water Heaters and Pressure Vessels

i. Simply state that this Chapter will not have changes in the 2012 code.

13. Discuss the significant changes to Refrigeration Chapter 11 of the 2012 NC Mechanical Code.

a. Slide 294: Chapter 11 Refrigeration i. There is continuing research on

refrigerants and new refrigerants will mostly likely be added for some time.

b. Slide 295: Chapter 11 Refrigeration cont’d i. This chapter is now more consistent

with the ASHRAE Standard.


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c. Slide 296: Chapter 11 Refrigeration cont’d i. Read or paraphrase and continue to

next slide.d. Slide 297: 1104.2.2 Industrial occupancies and

refrigerated rooms i. Read code text and to next slide for

change.

e. Slide 298: 1104.2.2 Industrial occupancies and refrigerated rooms cont’d.

i. The potential fire risk for anhydrous ammonia (R717) is very small in a code compliant machinery room.

ii. This change coordinates with ASHRAE Standard 15, Safety Standard for Refrigeration Systems.

f. Slide 299: 1107.2 Pipe enclosures i. You will continue to see changes in

the code that will align with the ASHRAE Standards.

g. Slide300: 1107.2 Pipe enclosures i. This has been re-written.

h. Slide 301: 1107.2 Piping location i. New text: Read text. ii. Note that refrigerant piping is not

allowed in an enclosed public stairway.

i. Slide 302: 1107.2 Piping in concrete floors i. This is exactly as it is written in

ASHRAE 15 standard. ii. It does not address the pipe duct

material. iii. PVC pipe ducts would be

acceptable.



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13.Discuss the significant changes to Hydronic Piping Chapter 12 of the 2012 NC State Mechanical Code.


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a. Slide 303: Chapter 12 Hydronic Piping i. New materials are introduced that

have been used in other countries without problems and that have meet the appropriate standards.

b. Slide 304: Section 1201.2 Sizing i. Why is this important? ii. In hydronic systems, some

components, like regulators, may require a different pipe diameter than the connecting piping in order to meet the demand of the system.

iii. It is not to be assumed that components can simply be the same size as the piping.

iv. Undersized piping can be subjected to greater stress and erosion.

v. Noise can become a problem due to increased velocity.

vi. Incorrect sizing can cause loss of system capacity, inefficient operation, and unsafe operation of the equipment.

c. Slide 305: Section 1201.3 Standards i. ASME B31.9 is a recognized

international standard for hydronic piping.

ii. This standard is intended to be applied to piping for water and anti-freeze solutions for heating and cooling, steam, steam condensate, air liquefied in limited sizes, pressures, and temperature limits.

iii. ASME B31.9 was developed in 1982 for commercial and multi-family building systems. It is considered a reliable method and is an acceptable alternative for determining materials for piping, joints, connections, and other system components.

d. Slide 306: Table 1204.2 Hydronic Pipe


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i. Four piping materials have been added to the Table of accepted materials for hydronic pipe.

e. Slide 307: Section 1202 Discussion i. PE-RT is manufactured to

ASTM F 2623.

f. Slide 308: Section 1202 Discussion cont’d. i. PE-AL-PE, not to be confused with

Pex-Al-Pex, must meet ASTM F 1282.

ii. The polyethylene does not have the cross-linked molecular structure of PEX.

g. Slide 309: Section 1202 Discussion cont’d. i. Ductile iron has been used for

hydronic systems in a number of locations without problems and both of these have been allowed in the plumbing code.

ii. They are now accepted for hydronic systems.

iii. Some international corporations requested this change.

h. Slide 310: Section 1202 Discussion cont’d. i. Paraphrase this information. ii. This piping comes in purple, green,

and blue.

i. Slide 311: 1203.8.2 Push-fit joints i. Section 1203 describes the joint and

connection requirements for piping systems.

j. Slide 312: Section 1203 Discussion i. Read and continue.

k. Slide 313: 1203.15.1 Heat fusion joints i. Read and continue.


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l. Slide 315: 1203.16 Polypropylene (PP) plastic i. Read and continue. ii. This starts the new sections for the

new materials. iii. If you can find some samples of

these new piping systems to pass around the classroom, it would add interest.

m. Slide 316: 1203.16.1 Heat-fusion joints i. Read and continue.

n. Slide 318: 1203.17 Raised temperaturepolyethylene (PE-RT)

plastic tubing i. Read and continue. ii. A little humor here would help. iii. This is dry material.

o. Slide 319: 1203.17.1 Compression-type fitting tubing

i. Read and continue.

p. Slide 320: 1203.17.2 PE-RT-to-Metal connections

i. Read and continue

q. Slide 322: 1203.18.1Compression-type fittings i. Read and continue

r. Slide 324: 1203.19 Cross-linked Polyethylene/aluminum/cross-linked polyethylene (PEX-AL-PEX) pressure pipe

i. Read and continue

s. Slide 327: 1203.18.1Compression-type fittings i. This begins coverage on changes in

requirements for radiant heating systems.

ii. Discuss why these systems are becoming more popular. These systems have been popular in Northern Climates for years.


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t. Slide 328: 1209.5.1 Slab on grade installation i. Insulation is now required below the

piping in radiant floor systems. ii. This improves the effectiveness and

efficiency of the system and save energy.

iii. There requirements for two arrangements.

iv. First, slab on grade.v. Read text. Without the insulation,

the ground would absorb a great deal of heat before it comes into equilibrium and allows the heat to rise into the space intended to be heated.

u. Slide 329: 1209.5.2 Suspended floor insulation i. Second, suspended floor

installations. ii. Read text. The insulation directs the

heat where it is intended instead of the space below.

iii. The insulation must be installed in accordance with the insulation manufacturer’s instructions.

iv. The instructions should include the requirement for an air barrier between the insulation and the space below unless the insulation has its own air barrier applied to it.

v. Slide 330: 1209.5.3 A thermal break required i. A thermal break is required to

prevent heat loss to the foundation.

w. Slide 331: 1209.5.4 Thermal barrier marking i. Just as in the Energy Code, the

insulating materials shall bear an R-value mark.

ii. These provisions were not covered in the Energy Code, so it is appropriate to include them in the Mechanical Code for this type of system.


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x. Slide 332: Questions ? i. As in any good class, ask if there are

any questions.

y. Slide 333: That’s all, folks! i. For CE approved classes, remind

the class to fill out the evaluation form and pick up their certificates.

ii. You may provide your contact information as well as the DOI contact information for additional questions.




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Extended Presenter Notes slides _______

End of Extended Presenter notes slides ______


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engineering lesson plan template - ncdoi. web viewthey divided the calculation into two part to...

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