John Swift, Jr., PE, LEED, CEM Principal- Cannon Design

Boston, MA

Labs21 2011 Annual Conference

Providence, RI

Utilizing Energy Recovery and Optimizing Air

Exchange Rates in Laboratory Buildings to Achieve

Optimal Energy and Air Quality Results

Labs 21 is a Registered Provider with The American Institute of

Architects Continuing Education Systems. Credit earned on completion

of this program will be reported to CES Records for AIA members.

Certificates of Completion for non-AIA members are available on

request.

This program is registered with the AIA/CES for continuing professional

education. As such, it does not include content that may be deemed or

construed to be an approval or endorsement by the AIA of any material

of construction or any method or manner of handling, using, distributing,

or dealing in any material or product. Questions related to specific

materials, methods, and services will be addressed at the conclusion of

this presentation.

This presentation is protected by US and International

Copyright laws. Reproduction, distribution, display and use of

the presentation without written permission of the speaker is

prohibited.

© Cannon Design, 2011

Learning Objectives: Learning objective 1: Understand current air exchange

recommendations in lab spaces looking at OSHA, ASHRAE and

NFPA standards.

Learning objective 2: Understand the benefits and challenges of

applying desiccant energy wheels for manifolded, central air handling

systems serving laboratory buildings.

Learning objective 3: Understand the benefits of dilution

assessments, dynamic air monitoring systems and MERV 16

filtration.

Overview

The presentation will discuss the

positive energy reduction impact

of reducing air changes in

laboratory spaces while

maintaining safe and healthy

indoor air quality levels for the

building occupants.

Designing Critical Duty Projects

Requires a Rigorous Process

Design Process

• Health

• Safety

• Protect Research

• Comfort

• Efficient Use of Resources

Air Exchange Rates in Laboratory Buildings

Health and Safety

• Safe Operating Practices

• Emergency Equipment

• Air Quality

• Air Changes

Air Exchange Rates in Laboratory Buildings

Protect Research

• Air Quality

• Redundancy

Air Exchange Rates in Laboratory Buildings

Comfort

• Optimize Indoor Environmental Quality

• Indoor Air Quality

• Natural and Artificial Light

• Thermal Comfort

Air Exchange Rates in Laboratory Buildings

Efficient Use of Resources

• High Performance Design

• Energy Efficient Building Systems

• Ease of Maintenance and Service

Air Exchange Rates in Laboratory Buildings

Source Air Changes per hour

NFPA 45- 2000 NFPA 45-2011

8 ACH occupied, 4 ACH unoccupied No min/max

ASHRAE- 2007 Handbook and Lab Design Guide

6 – 12 ACH*

OSHA 1910 NIH Guidelines

4 – 12 ACH 6 ACH

Air Exchange Rates in Laboratory Buildings

• No codes- just guidelines

• No standard industry practice

• Higher ACH do not assure optimized Ventilation Effectiveness

Air Exchange Rates in Laboratory Buildings

Factors in Determining Optimized Rate

• Cooling Loads- External and Internal

• Exhaust Make-up Requirements

• Ventilation for Optimized Air Quality

Air Exchange Rates in Laboratory Buildings

Ventilation for Optimized Air Quality

• Model-based design process

• Computational Fluid Dynamics (CFD)

• Optimize air flow to maximize ventilation effectiveness

• Measure and provide dynamic ACH control

• Eliminate turbulence at fume hoods and bio-safety cabinets

Air Exchange Rates in Laboratory Buildings

1. Fresh Outdoor Air (Hot and Humid) is Passed Through the Wheel

2-3. Outdoor Air is

Cooled, Dehumidified then

Supplied to HVAC System

4. Exhaust Air is

Pulled from the Space

(Cool and Dry)

5-6. Exhaust Air is Heated and

Humidified then Sent Outdoors

How It Works: (Cooling)

Energy Wheels

Outdoor Air

80 DEG 75 GR.

75 DEG 60 GR.

95 DEG 120 GR.

Return Air

Supply Air

90 DEG 105 GR.

Exhaust Air

Outdoor Air

54 DEG 25 GR.

72 DEG 32 GR.

0 DEG 4 GR.

Return Air

Supply Air

18 DEG 11 GR.

Exhaust Air

Cooling Mode Heating Mode

TYPICAL PERFORMANCE BUFFERS SPACE FROM EXTREME OUTDOOR AIR CONDITIONS

Energy Wheels

Function of the Purge Section

• Purge dirty air trapped in wheel media as it rotates from the dirty to the clean airstream

• Purge angle adjustable and driven by the pressure differential existing between the outdoor air and return air streams

• Proper setting shown to limit carry-over to well below .045% in actual field commissioning tests

Energy Wheels

Codes: Energy Wheels in Laboratories

NFPA 45 requires documentation (test data and field experience) that exhausted

contaminants are not transferred by the total energy recovery wheel.

“Devices that could result in recirculation of exhaust air or exhausted

contaminants shall not be used”

IBC 2006 and 2009

Laboratories are not considered hazardous exhaust systems if contaminants

are below 25% of flammability limit and below 1% medial lethal

concentration (lab assessment analysis)

Duct systems can be manifolded and wheels used if contaminants are not

recirculated

References 90.1 which recommends total energy (>50% total energy recovery)

Energy Wheels

ASHRAE Standard 62

Purpose:

To specify the minimum ventilation rates and indoor air quality that will be acceptable to human occupants and are intended to minimize the potential for adverse health effects.

Codes: Energy Wheels in Laboratories

ASHRAE:

In a recent interpretation of ASHRAE 62.1-2007, has indicated that mandatory

section 5.16.3.4 “does not allow for recirculation of any amount of Class 4 air nor

does it allow the use of heat recovery equipment which will result in recirculation of

Class 4 air via leakage, carryover or transfer from the exhaust side of the system.

It is possible to install heat recovery equipment, such as run-around loops, heat

pipes or impermeable, plate-type heat exchangers, which will allow heat recovery

from the Class 4 exhaust airstream while preventing cross-contaminated flow.”

Energy Wheels

Codes: Energy Wheels in Laboratories

ASHRAE

Fume hood exhaust air is generally classified as Class 4 air by ASHRAE 62.1-

2007. Since this section is a mandatory requirement of ASHRAE 62.1-2007,

non-compliance would mean that the design does not meet the LEED

prerequisite for compliance with ASHRAE 62.1-2007 which means the project

could NOT be LEED certified. Project design teams will need to indicate how

they will address compliance with ASHRAE 62.1-2007 while taking manifold

fume hood exhaust air through proposed enthalpy wheels.

Energy Wheels

Codes: Energy Wheels in Laboratories

ASHRAE

At a minimum the mechanical code identifies certain hazards that cannot be

connected to a manifold exhaust system and at minimum these should be

separated from the enthalpy wheel exhaust system. In addition, technical data

reports “virtually no cross-contamination (independently certified to be less than

0.04 percent)” should be provided for EHS records. This should be requested from

all potential vendors or specification should be limited to vendors meeting the

agreed upon criteria and provided to EHS for review.

Energy Wheels

Critical Duty Project Design Process

•Labs are not all the same – evaluate the purpose of the facility and

establish an initial design approach

•Complete a full Risk Assessment Analysis involving the Health and

Safety officers

•Provide independent carry-over test data for use by owner and

code authorities

•Complete accurate full benefit and life cycle cost analysis,

highlighting both energy savings, chiller – boiler impact and carbon

footprint

•Provide a critical duty wheel designed specifically for laboratory

environments – limit contaminant carry-over, corrosion resistance,

antimicrobial surface, anti-stick, etc.

Design Process

Critical Duty Project Design Process (continued)

•Provide experienced startup to review installation, airflows,

pressures, purge settings, etc.

•Coordinate SF6 testing and commissioning report after final air

balancing but prior to occupancy

•Complete real time contaminant testing (TVOC) and

commissioning report after occupancy and use of facility to

document wheel performance

•Monitor system performance, pressures, flows and purge

performance (HSM) and alarm if problem with system

•Trend energy savings over time and highlight benefits provided

with owner and designer

Design Process

Fume Hood Flexibility

Flexibility

Fume Hood Exhaust Capacity Assessment

Location Fume Hood Type LF of hood

exhaust

capacity per

floor

Hood

length

(ft)

Max Fume

Hoods per

floor

Bldg X Standard (100 CFM/LF) 320 8 40

Bldg Y Standard (100 CFM/LF) 450 8 56

Bldg X Low Flow (60 CFM/LF) 540 8 68

Bldg Y Low Flow (60 CFM/LF) 740 8 93

Sample Calculation

Dilution Assessment

Dilution Assessment

Energy Recovery Wheel Carry-over Analysis: “Spill Scenario”

Dilution Assessment

Energy Recovery Wheel Carry-over Analysis: “Spill Scenario

Dilution Assessment

Findings:

Under this worst case spill scenario, none of the chemicals listed

would be introduced to the space at more than 6% of the threshold

limit value allowable (exposure thought to be safe to occupant - 8

hours per day, 5 days per week).

As it relates to recent interpretations by ASHRAE, it is important to

point out that ASHRAE allows more than 10 times this amount, or

100% of the TLV to be re-entrained into the fresh air intake from the

exhaust fans during a spill event (Appendix F and AIHA/ANSI

Standard Z9.5).

Dilution Assessment

Findings:

None of the flags shown for the 5 chemicals listed in the summary

analysis represent a health risk.

All are shown for potential odor detection under the spill scenario.

The chemicals used for this analysis came from a listing of chemicals

not detected by a monitoring system, and don't appear to be

chemicals routinely used.

Of those listed as commonly used chemicals, none were flagged. In

addition, the materials with extremely low odor detection limits

shown - i.e. mercapatans - are used in very small quantities and will

not typically be available for spill in a 500 ml quantity.

Dilution Assessment

Findings:

Based on the analysis there is essentially no health risk shown.

During a worst case spill scenario, there will likely be a slight odor

detected in the supply air for a very short period.

It is also likely that there would be odor detected under this spill

scenario due to the re-entrainment - even if the wheel were not to be

used.

Dilution Assessment

Dynamic Air Monitoring

Dynamic Air Monitoring

Dynamic Air Monitoring

Health and Safety Monitor Capabilities

•Limit Carry-over in VAV, variable pressure environment optimizing

health and safety

•Real time performance monitoring and trending

•Real time energy savings and accumulation

•Real time airflow measurement

•Alarm if purge pressure is lost

•Greatly reduce fan horsepower use

•Automatically determines field purge setting

•Enhances Field commissioning

•Enhances Cross-contamination testing

•Remote monitoring

Dynamic Air Monitoring

Effect on Particle Count

room particles/cu ft = supply air particles/cu ft + (100,000

particles/sec / airflow in cu ft/sec) 3-10 micron 1.0-3 micron .3 - 1.0 micron

MERV 14 (nominal 90-95 filter): >90% >90% 75%-85%

HEPA @ 99.97%: -- -- 99.97%

Filtration

Filtration

Case Study

King Faisal Specialist Hospital

Biotechnology Research Lab

Riyadh, Saudi Arabia

Case Study

Climate Analysis

Temperature Range

Monthly Diurnal Averages

Dry Bulb x Dew Point

Psychrometric Chart

Case Study

Potable water service is

much more difficult to

supply at consistent,

cost effective levels.

Energy Use per 1000 gallons of water delivered

0

2

4

6

8

10

12

kWh

per

100

0 G

allo

ns Well Water

Surface Water

Brackish Water

Sea Water

Energy = Water

EXHAUST

HOOD

SUPPLY AIR -

CHILLED BEAM

(TYP.)

EXHAUST

REGISTER

(TYP.)

Supply Air provided by

Chilled Beam System

4 ACH & 8 ACH Layout

Case Study

EXHAUST

HOOD

SUPPLY AIR

DIFFUSER (TYP.)

EXHAUST

REGISTER

(TYP.)

Supply Air provided by all air system (In order to achieve high air

change rate, chilled beams are not used.)

12 ACH Layout

Case Study

Four Models Compared:

• 12 Air Changes per Hour

• 8 Air Changes per Hour

• 4 Air Changes per Hour (unoccupied)

• 8 Air Changes per Hour, chilled beams rotated 90 degrees (perpendicular)

Case Study

Velocity Vector

Case Study

Particle Tracking

PARTICLE

START POINT

PARTICLE END

POINT

PARTICLE END

POINT PARTICLE

START POINT

Case Study

Local Mean Air Age

Case Study

Room Temperature

Case Study

Air Change Effectiveness

Case Study

CO2 ppm

Case Study

Energy Analysis

Case Study

Case Study

Case Study

Summary

A state-of-the-art system that is safe, healthy

and effective.

Optimal thermal comfort and air quality.

Controlled space pressurization based on

fume hood usage and pollutant control.

30+% energy savings.

Flexibility for future iterations of space

planning and equipment concentrations.

Optimized construction costs by reducing air

handling unit sizes, duct sizes, shaft sizes and

penthouse sizes throughout the building.

John Swift, Jr., PE, LEED, CEM jswift@cannondesign.com

Labs21 2011 Annual Conference

Providence, RI

This concludes The American Institute of Architects

Continuing Education Systems Program

Utilizing Energy Recovery and Optimizing Air Exchange Rates in Laboratory

Buildings to Achieve Optimal Energy and Air Quality Results