Your Facilities Management Resource on the Internet
Entire Site (current)
FMLink: Your Facilities Management Resource on the Internet
Like this Article?
Sign up for FMLink's Industry-Wide Newsletter!

Companies related to the content on this page
Gold Sponsors
Silver Sponsors
300 North Limited
Abrasive Resource
Accurate Building Maintenance
Accuware Inc.
ACE Lifts Ltd
Action Air, LLC
Action Services Group
ADEN Services
ADMS Technologies
Advanced Planning Technologies
Advanced Specialty Contractors
AEG Power Solutions
Aggreko Cooling Tower Services
Air Cycle Corporation
Air Link International
AirPac, Incorporated
AJM Nino Corp.
Albright Electric LLC
Alexander Services
Allerair Industries
American Air & Water, Inc.
Americart USA LLC
Andrews Air Conditioning Refrigeration
AquaPro Solution
Ashlar FM
Atlas Foundation Company
Australian Electronic Water Conditioners
Axxess 28 Ltd
BarScan, Inc.
BESTechnologies, Inc.
Better Managed Contracts
Black Gold Industries (BGI)
BLU-MED Response Systems
Blue Reserve Water
Bluff Ramps
BMI Imaging Systems
Bridgepoint Systems
C.E. Electronics - Acoustics Group
CAD Management
CAFM Explorer
California Waters, LLC
Cambridge Sound Management
Camlar Ltd
Capital Cleaning - Middle East
Caterpillar, Inc.
CCM Heating & Air Conditioning
Chadís AC Direct
Citywide Property Owners Network
Climate Contingency Services Ltd
Com Tek CADD Company
Complete Facility Solutions
Component Hardware Group
ConneXion E-Solutions
Contract Services Group, Inc.
Cooper Lighting
Cornell Storefront Systems
Corrigo Incorporated
CWorks Systems, Inc.
D.L. Vaughn
Daintree Networks
Datacard Group
Delray Lighting Inc.
DG Consulting
Digital Lumens
DP Air Corporation
DRI-STEEM Corporation
Dry Force - Austin
Duro-Last Roofing, Inc.
DWM Facilities Maintenance
EAM University
Earth Guard Pest Services
Earthservice Drainmaster Inc
Eastco Building Services
Easterday Building Maintenance
eData Collectors, Inc.
eFACiLiTY - Sierra ODC Private Limited
Eisenbach Consulting, LLC
EMCOR Facilities Services
Energy Effiicient & Eco Solutions
Energy Tech Solutions, LLC
Environmental Consulting & Tech., Inc.
Envirotech Office Systems Inc.
EPAC Software Technologies
Equipment Innovators
Escom Properties, Inc.
EverGlow NA, Inc.
Excalibur Extrusions
EXTECH/Exterior Technologies Inc.
Facilities Systems & Management
Facility Engineering Associates, P.C.
Facility Planning Partners LLC
Fackler Commercial Roofing
Falcon Waterfree Technologies
Fike Corporation
Flora Terra Landscape Management
Fluke Corporation
FM Magazine
Forbo Flooring Systems
Friedrich Air Conditioning Co.
Gates General Contractors
GeoPal Solutions
Governair LLC
Green Belt Turf Farm
GreenTech Solutions Group
Hecei Roof Coating Systems, Inc.
Hope Energy Group, LLC
Huntair, Inc.
IFCS inc.
Impac Systems Engineering
INFORMED Corporation
Innovative -IDM
Instruments Direct
International Innovative Systems
Irving's Plumbing Supplies
Juice Bar EV
Kenall Lighting
Kimball Office
Kingdom Communications LLC
Kondor Security
Leum Engineering
Libtra Reliance Properties
Lighting Plastics of Minnesota
LIKARR Maintenance Systems
Lutron Electronics Co., Inc.
LYNCH Janitorial & Cleaning,LLC
Major Industries, Inc.
Mammoth, Inc.
Manhattan Software
McFarland Johnson, Inc.
MCS Management Services
MechoSystems, Inc.
Met-Tile, Inc.
Metis Secure Solutions
MicroMain Corporation
MTU Onsite Energy Corporation
Multi-Link, Inc., Inc.
National Vending
Natural Choice Corporation
NetZero USA
Newly LLC
Nexxus Lighting, Inc.
NFS Hospitality Corporation
No1 Facilities Management
Noncontact Meters
Norspec Filtration Ltd.
Nu Flow
Overly Manufacturing Company
Panduit Corporation
Parterre Flooring Systems
PCE Instruments UK Ltd
Peak Exterior
Peak Xteriors
Peelle Technologies
Pegasus Associates Lighting
PenBay Solutions LLC
Perfection Machinery
Performance Resource Partners
Philips Lighting Company
PHS West
Polar Shades
Preferred Gas Plumbing & Pool Heating Su
PRSM Association
Q Systems Engineering, Inc.
QA Graphics
Quality Attributes Software (QAS)
Raritan Building Services Corporation
RCI Services Inc.
Reliance Foundry Co. Ltd.
Relocation Advisers Ltd.
Rentokil Specialist Hygiene
RJS Pest Management
Rooftop Solutions
Russelectric Inc.
S&H Energy Services
SafePak Corporation
SBS Window Cleaning
Sedgwick Heating
Service Works Group
Servicemax Inc
Showalter Roofing Services, Inc.
Sidel Systems USA Inc.
Signum Facilities Management Ltd
Simple Solutions FM
Skarnes Inc.
Skire, Inc.
Skyline Sky-Lites, LLC
Smart Start Lighting
Smartpro Facilities
SOL Inc.
Solaronics Inc.
Southern Maintenance Solutions UK Ltd
Specialized Storage Systems Inc.
Specialty Bulb Co. Inc.
Speech Privacy Systems
St Paul Pipeworks
Stellar Energy
Structural Anchor Supply
Superior Electric
Superior Property Solutions
T.W.E.A.K. Services
Tandem Chillers
Tank Lining Company
Temtrol, LLC
Thatcher Workplace Consulting
TMA Systems
Total Solution Provider
Tristar Power Solutions
Trix Systems, Inc
TUV-SUD FM (Wallace Whittle)
UGL Services
USA Security
Venmar CES, Inc.
Ventrol Air Handling Systems, Inc.
Videx, Inc.
Virkoh Facility Management Services
Vokes Filtration (Pty) Ltd
Wholesale Pumps
Wired 4 Sound, Inc.
ZF Consulting
[P-2] Precision Paragon
Components of Good Indoor Air Quality

July 2015—Good air quality is an important component of a healthy indoor environment. Poor air quality leads to sick building syndrome complaints, lost worker productivity, and tenant health complaints such as allergic reactions, nausea, chronic fatigue, and respiratory problems.

Good indoor air quality (IAQ) includes the following elements:

  • Acceptable temperature and relative humidity (RH)
  • Controlled airborne contaminants
  • Adequate distribution of ventilation air

Acceptable Temperature and Relative Humidity

IAQ is affected by temperature and RH because thermal comfort concerns are the cause of many complaints about poor air. Temperature and humidity are also among the many factors that affect indoor contaminant levels. Bacterial growth and fungal growth are promoted at humidity levels above 60 percent.

Controlled Airborne Contaminants

The contaminants that produce indoor air pollution include carbon dioxide, smoke, dust, odors, and biological contaminants such as mold and bacteria. Some of the most dangerous pollutants result from the gas released by materials used in newly finished construction and space furnishings. Indoor air may contain tobacco smoke; gaseous emissions from fabrics, furniture, and adhesives; and offensive odors from equipment, solvents, and people.

The growth of biological contaminants, including bacteria, mold, and fungi, can be controlled by keeping systems clean and dry. Biological contaminants thrive in areas that are dark, moist, and laden with nutrients. Design characteristics that help keep ducts and equipment clean include sloped drain pans; easily cleaned, nonporous surfaces; and easy accessibility to the ducts. Sloped drain pans prevent water from building up and developing into nutrient-filled slime. Easily cleaned, nonporous surfaces will not hold moisture, eliminating the need for duct-lining materials. Easy accessibility to the ducts for cleaning is especially important in areas where dirt builds up because of the turbulence of direction change or the presence of some obstructing device such as a damper.

Adequate Distribution of Ventilation Air

The primary purpose of ventilation is to control IAQ by diluting polluted indoor air with less contaminated outside fresh air. In many instances, ventilation air alone will reduce IAQ problems. Improperly balanced HVAC systems can create stagnant areas in an otherwise properly ventilated building. In certain instances, additional air filtration and treatment may be necessary.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has established guidelines for determining ventilation rate and procedures to assure air quality. These guidelines are accepted across the United States. Building owners and managers should familiarize themselves with Standards 62 through 89 in particular, keeping in mind that local codes can amplify or supersede these ASHRAE guidelines. The ventilation required for any given building varies according to the number of people who occupy it and the size of the space. People give off body odors that require a minimum of 5 cubic feet per minute (cfm) of ventilation air per person, or 0.05 cfm per square foot for satisfactory dilution.

The amount of outside air considered adequate for proper ventilation has varied substantially over time. The standard in effect when the HVAC system for a particular building was designed may have had a different requirement than is currently recommended. The current standard is ASHRAE 62-1989, Ventilation for Acceptable Air Quality, which recommends 15 to 20 cfm per person, based on the type of occupancy. The previous standard of 5 cfm per person appeared in 1981 to supersede the 1973 pre-energy crunch standard of 15 cfm to 25 cfm per person. Always check the latest publications of ASHRAE, Building Officials and Code Administrators (BOCA), and EPA to learn the standards that are in effect.

New technologies are being used in the struggle to maintain acceptable IAQ levels while battling the high cost of cooling/heating the outside air needed for make-up air. Enthalpy wheels and makeup air units (MAUs) are gaining popularity with design engineers and are becoming commonplace in buildings where general exhaust air is dumped to the outside. The enthalpy wheel is a heat recovery unit that operates on the air-to-air principle. Many existing systems can be retrofitted with an enthalpy wheel. The wheel rotates very slowly and is cooled by the cool, dry exhaust air.

For example, the return air in the summer is approximately 70 degrees F with an RH (relative humidity) of 40 percent. The wheel passes through the exhaust air where it gives up heat to the cooler 70 degrees F return air. The cooler wheel continues around until it passes through the warmer (90 degrees F with 80 percent RH) outside airstream. The cooler enthalpy wheel passing through the warmer airstream absorbs the warm, humid air and continues around to the return air duct where it again gives up heat to the cooler exhaust air.

The enthalpy wheel can be used year-round and can reduce energy consumption by a considerable amount, making it more cost-effective to introduce fresh air into a building. In newer systems, an MAU is installed on a roof or in a mechanical space. The MAU can be designed to use an enthalpy wheel that is tied into the fresh air supply duct and the exhaust air discharge duct of the unit. Exhaust air temperatures can range from 70 degree F to 74 degrees F, with an RH level between 30 and 50 percent. Outside air temperatures fluctuate depending on location and season. Energy costs can be reduced by as much as 40 percent when an enthalpy wheel is used in conjunction with an MAU.

This article is adapted from BOMI International's course Air Handling, Water Treatment, and Plumbing Systems, part of the SMA and SMT designation programs. More information regarding this course or the new High-Performance certificate courses is available by calling 1-800-235-2664. Visit BOMI International's website,

  © 1996-2017 FMLink Group, LLC    301.365.1600             Privacy Policy           About FMLink