Foundation of HVAC design development

HUNTER BUILDINGS, LPBy Luis Santiago, PE,PMP

Engineered Systems in Hunter’s Fabrication

Civil / Structural Mechanical:

Plumbing HVAC Fire Protection Gas Detection

Electrical

Engineered Systems - Comparison

NOTE: ALL OF THE ABOVE ENGINEERED SYSTEMS ARE NOT CRITICAL NOR IMPORTANT FOR PROTECTING THE INDOOR ENVIRONMENT.

Reactive (Responsive): Structural Electrical Mechanical:

Plumbing Gas Detection Fire Protection

NOTE: HVAC IS THE MOST CRITICAL AND MOST IMPORTANT OF THE ENGINEERED SYSTEMS AFFECTING THE INDOOR ENVIRONMENT OF THE HUNTER’S BUILDINGS.

Proactive (Preventive): Mechanical:

HVAC

Hunter’s Building Site Placement

Electrical Hazardous Classifications: Flammable Gases, Air-Vapor, or Liquid mixtures

▪ Class 1, Division 1 (Normal)▪ Class 1, Division 2 (Abnormal)

Combustible Dusts▪ Class 2, Division 1 (Normal)▪ Class 2, Division 2 (Abnormal)

Ignitable Fibers or flying▪ Class 3, Division 1 ((Normal)▪ Class 3, Division 2 (Abnormal)

Our Buildings are mostly sited in Hazardous Locations: Gasoline storage Dispensing areas (Tank Trucks) Utility gas plants Liquefied petroleum gas plants Oil refining plants

Most vulnerable engineered system Electrical

Identifying risks Outdoor Contaminants (Combustion gases / Air-Vapor mixtures / Fire / Smoke / Microbial /

Particle Counts (Dusts, viruses, etc.)): Toxic

Cause: Fuels, H2S, HCN, HCL, CL, CO > 2.0%, CO2 > 1.5%, etc.Effect: Harmful or lethal to occupants

Flammable Cause: VOCs, SOx, NHx, etc.Effect: They burn rapidly or ignited easily when exposed to ignition source (arc, flame, heat) due to flash point, auto-ignition point, or fire point.

Explosive Cause: Concentration by volume LEL/LFL (Usually between 1.5 to 7.5 %)Effect: Potential explosion hazard

ConductiveCause: Ionized and unstable atmosphereEffect: Arc-Flashing, Sparkling

Electrical Equipment failure -> “Building Safety” is compromised

POTENTIAL risks of outdoor contaminants within workplace (i.e.; Occupants): Dangerous (may cause fire, smoke, explosion, or combination) Harmful (may cause serious or long-term health condition) Lethal (may be fatal, causing death)

USA Regulatory Agencies

International UL CSA ETL CE ATEX

Federal EPA OSHA NFPA NEC FERC ANSI / ASTM

State DOT EHS

Local/City Ordinances

NOTE: All of the above agencies have something in common. They all look for “End-user Risk Response Plan”.

Indoor Air Quality (IAQ)

HVAC system is the heart to deal with most IAQ issues while protecting all occupants within their workplace by assuring an indoor environment quality.

What major root-causes influence IAQ? Hazardous contaminants (Toxic, flammable, explosive, or combination) Biological contaminants (Microbial/Bacteria/Virus/Fungi/Mold) Physical contaminants (airborne particulates, such as: dust, fiber, etc.)

Reasons of IAQ issues: Insufficient natural or mechanical ventilation (OA) Poor air distribution and recirculation (Air pockets: lighter-than-air / heavier-than-air) Poor HVAC design performance (CFM/tonnage versus static pressure, horsepower,

efficiency) How can we solve IAQ problems? Isolation = purging and pressurization of the building inside to separate external

pollution in the surroundings out of the building indoor space. Dilution = increases indoor air density by purging protective clean gas/air into the

workplace. Filtration = airborne particles / dust / mold growth prevention.

HVAC Design Accountability

Indoor air conditioning (T & % RH) Thermal comfort zone

Temperature (68 to 75 °F) Relative Humidity (45 to 60% RH)

Indoor air quality (IAQ) Good public health, safety, and welfare

Otherwise: Sick Building Syndrome (SBS). (Ex. Headaches, nausea, itching eyes, respiratory difficulties, skin irritation, and fatigue.)

Noise criteria (ruled by EPA , OSHA, NFPA, IBC, IMC, ASHRAE) 75 dBA (32 hours exposure) 80 dBA (16 hours exposure) 85 dBA (8 hours exposure = 1 shift) 90 dBA (4 hours exposure) 95 dBA (2 hours exposure) 100 dbA (1 hour exposure) 105 dbA (1/2 hour exposure)

Energy Conservation (Horsepower, kW, or BTUH) Lower static pressure Longer on-off cycling Implementing airlocks (0.4 tons loss per airlock) Implementing vestibules (2.5 tons loss per vestibule) Single-swing door (3.5 tons loss per each door)

Cost Reduction/Savings: Cost of Conformance

Cost-Benefit Analysis of Indoor Air Quality

MONEY SPENT (INVESTED) DURING THE PROJECT TO AVOID FAILURES

Costs of Conformance: Prevention costs < 1 % (build

a quality product) Time to do it right Training Database Equipment

Appraisal costs (assess the quality of the product) Field Testing Inspections Quality audits

MONEY SPENT (WASTED) DURING AND AFTER THE PROJECT BECAUSE OF FAILURES

Costs of Non-conformance: External Failure Costs (failures

found by the customer) Liabilities >> 1 % Warranty work Loss of business and reputation

Internal Failure Costs (failures found by the project) Rework Scrap Unnecessary stock

HVAC Engineered System – Project Comparison

PREVIOUS PROJECTS ANOMALIES

No separate electrical power source for purging and pressurization system (NFPA 496 violation).

Air pockets (air stagnation points above ceiling and/or below floor).

Long flexible-ducted branches (increase static pressure as well as HVAC equipment load).

Fire dampers in 1-hour fire-rated walls (waste of money in labor and material).

Hunter’s building sited in hazardous location (Class 1 or 2) without pressurization system (NFPA 496 violation).

CURRENT PROJECTS IMPROVEMENTS Independent electrical power source for

purging and pressurization system (NFPA 496 compliant and public safety).

Ducted return air (Plenum and conditioned space).

Flexible duct limited up to 5’-0” long plus rigid duct.

Considering no fire dampers in 1-hour fire-rated walls per NFPA/IBC code (cost savings).

If Hunter’s building is sited in hazardous location (Class 1 or 2), purging / pressurization system must be provided per NFPA 496 requirement.

Cost-Benefit Analysis of Indoor Air Quality

Cost-Benefits: Thermal comfort No IAQ issues (contamination control) Higher performance Low operating costs Low maintenance costs Public health environment (workplace) Public welfare (occupant load) Public safety

REMEMBER

HVAC issues related to IAQ are important in the design of new buildings as well as in the remediation of existing buildings to comply with nowadays business demand.

Thus, we will stand out from the competition by “added value” to the business development on this challenging business market world.

THANKS