Shearman And Sterling

Real Estate, Modern Skyscrapers

Jun 01, 1997

New Standards are in the Air: ASHRAE's Proposed Standard on Indoor Air Quality


Jump to...


In the early 1990s, the U.S. Environmental Protection Agency ("EPA") identified indoor air pollution as among the top five environmental risks to public health. EPA based this finding on two primary factors: first, there are thousands of air pollutants in the indoor air environment, and second, indoor exposures to air contaminants are two to five times higher than exposures out-of-doors.1 ASHRAE has proposed new standards for indoor air quality ("IAQ") applicable to building designers and owners. The proposed Standard 62-1989R, entitled "Ventilation for Acceptable Indoor Air Quality," revises an earlier ASHRAE standard and establishes industry standards for ventilation, source management and air cleaning to achieve acceptable IAQ conditions. The original Standard 62-1989 was primarily a design standard for new construction and large renovation projects and, thus, had limited impact. The revised standard goes beyond the design stage and includes system start-up for construction and renovation projects as well as operations and maintenance standards for both new and existing buildings. As drafted, Standard 62-1989R applies to "commercial, institutional, and residential building spaces intended for human occupancy."

ASHRAE recently closed the first public review of Standard 62-1989R and currently is reviewing comments. A second public review of the draft standard may be held later in 1997 to respond to the comments made during the first review period.


Scope and Application


 While ASHRAE standards do not by themselves have the force of law, they are often adopted by states in their building codes. The standards also serve to establish a standard of care for architects, engineers and building owners and managers. Failure to comply with ASHRAE standards is often used as evidence of negligence against a building owner or manager.2

 Standard 62-1989R applies to "commercial, institutional, and residential building spaces intended for human occupancy." According to ASHRAE representatives responsible for drafting Standard 62-1989R, Standard 62-1989R's requirements relating to operations and maintenance for ventilation systems can be interpreted to apply to both new and existing buildings. However, these representatives believe that any state adopting Standard 62-1989R is likely to limit its scope to new buildings and renovation projects.

 In the proposed standard, ASHRAE has established requirements for ventilation design, minimum ventilation rates and operation and maintenance standards for different types of indoor spaces. The proposed revision separately defines "acceptable indoor air quality" and "acceptable perceived indoor air quality."3 Acceptable IAQ is defined as "clean" enough that "there are not likely to be known contaminants at concentrations leading to exposures that pose a significant health risk." Acceptable perceived IAQ means that a "substantial majority of occupants express no dissatisfaction on the basis of odor and sensory irritation." Both types of IAQ must be achieved under Standard 62-1989R.

Standard 62-1989R divides the ventilation rate (the rate at which air is supplied to or removed from a space for the purpose of controlling air contaminant levels, humidity, or temperature within the space) into two components: a "building component" and a "people component." The first is dependent on the contaminant contribution of the building (i.e., outgassing from furnishings and carpets), and the latter on its occupancy rate. Air requirements are reduced if low-emissivity furnishings are used, a departure from the original standard currently in place, which specifies a cubic-foot-per-minute ventilation rate for each type of building.

In addition, the standard:

  • Requires greater consideration of ventilation system inefficiencies. Ventilation system efficiency is determined by the rate of outdoor air supplied to the occupied zones served by a ventilation system divided by the actual outdoor air rate supplied by the system as measured at its outdoor air intake. The standard provides guidance on ventilation system design, installation and operation and maintenance, ensuring that the system will be able to perform as intended and attains the desired performance efficiency.
  • Considers chemical, physical and biological contaminants, as well as factors such as moisture and temperature, that can affect human health and perceived air quality.
  • Requires that systems have adequate access for maintenance, and incorporates a section dedicated to HVAC operation and maintenance procedures. The prescribed maintenance program includes inspection, cleaning, calibration, verification of pressure relationships, and adjustment and replacement as needed of various components of the ventilation system. Ventilation system design documentation and inspection maintenance records must be retained in an accessible location for the life of the applicable system equipment. 

Different requirements apply to different types of buildings, as follows:

Commercial or institutional buildings shall comply with:

  • Section 5, General Requirements. This section requires documentation of design criteria, evaluation of outdoor air quality and outdoor air intakes and classification of air and recirculation limitations. It also provides standards for mechanical ventilation systems, natural ventilation systems, building construction and fuel-burning appliances. 
  • Section 6, Design Ventilation Rates. This section provides procedures for calculating ventilation rates for different ventilation system types.
  • Section 7, Construction and System Start-up. This section applies to new ventilation systems and the buildings they serve during and soon after construction. It also applies to existing buildings when remodeling or other renovation work takes place. During the construction phase, this section requires the use of filters, protection of building materials, isolation of major construction areas, notification of construction, and review of any substitutions of materials or equipment. System Start-up establishes minimum requirements for starting up ventilation systems, including air balancing, testing of drains, drain pans and damper controls, pre-start cleaning, purging of major construction areas, inspection and documentation.
  • Section 8, Operating and Maintenance Procedures. Under this section, a responsible party must be appointed for maintenance and operation purposes, and procedures for pre-occupancy, normal occupancy and off-hours ventilation system operation must be established. Section 8 also requires a preventative maintenance program, including documentation, filter and equipment maintenance, and airflow measurement, to ensure that the ventilation system is operating in accordance with the design.

 Residential buildings, including single-family residential buildings, boarding houses, and dwelling units of multi-family buildings, must comply with Section 9 requirements regarding ventilation, construction and operation and maintenance requirements. Section 9 establishes minimum rates for exhaust capacity and outdoor air requirements for ventilation. This section provides that one of three methods, Mechanical Ventilation, Demonstrated Ventilation, or Natural Ventilation, must be selected in connection with outdoor air requirements. The requirements for residential buildings also establish selection, installation, operation and maintenance procedures for ventilation systems and equipment.

 ASHRAE has determined that the requirements for supply rates of outdoor air for ventilation for commercial or institutional buildings should be based on the assumption of a smoke-free environment. Guidance is provided for additional ventilation and architectural requirements if smoking is permitted.


Comparison to OSHA


With the exception of certain proposed Occupational Safety and Health Act ("OSHA") regulations, which are limited to industrial and manufacturing operations, there are no federal laws or regulations on IAQ. In April 1994, OSHA issued a proposed rule for indoor air quality standards in general, non-industrial work environments. The proposal would have required employers to develop a written indoor air quality compliance plan and implement the plan through actions such as inspection and maintenance of building systems. The proposed regulations also would have required employers to implement controls for specific contaminants and their sources such as outdoor contaminants, microbial contaminants, maintenance and cleaning chemicals, pesticides and other hazardous chemicals within indoor work environments. Provisions for the reduction or elimination of environmental tobacco smoke were also included in the proposed OSHA regulations. After months of public hearings, however, OSHA's proposed rule has not been adopted as a final regulation.


Landlord/Tenant Issues


Indoor air quality has been a source of friction between landlords and tenants for at least the last decade, certainly since the advent of "sick building syndrome". One can anticipate that tenants with significant negotiating leverage will now argue that landlords should adhere to the ASHRAE standards with respect to the leased premises. But this position raises, in turn, a series of corollary issues.

  • If the landlord agrees to adhere to such standards, will it do so only upon the completion of a renovation of the building? Will the build-out of the tenant's space constitute a renovation for these purposes? (In a related vein, tenants may well require that landlords comply with Section 7, Construction and System Start-up, in the build-out of the tenant's premises and in the renovation of other space within the building.)
  • f the landlord agrees to adhere to the ASHRAE standards, will the costs of compliance be reimbursable by the building tenants? To the extent that such adherence is not required by law, landlords may well discover that the costs of capital improvements and ongoing maintenance required to comply with the ASHRAE standards cannot be passed through to tenants under typical operating expense provisions.
  • Should the responsibility for adherence to the ASHRAE standards only be that of the landlord? To the extent that portions of HVAC systems, such as the distribution systems and ductwork within the premises, are required to be maintained by the tenant, should some of the responsibilities for adherence to the ASHRAE standards also fall to the tenant?

 Finally, the ASHRAE standards include both a "building component" and a "people component". Certainly the latter would be within the control of the tenant, and any requirement that the landlord adhere to the ASHRAE standards should at least make certain assumptions about compliance by the tenant with occupancy levels and so on. However, even the building component may to some extent be within the control of the tenant. If outgassing from carpeting and other furnishings contributes to the presence of contaminants, should the tenant be required to effect purchases which will minimize such contaminants or, at the very least, relieve the landlord of responsibility to the extent that the standards are not complied with because of the presence of contaminants emanating from these sources?



The ongoing developments and review of ASHRAE's proposed standard have raised the anticipation that there will be a workable set of IAQ guidelines. Written in code-compatible language, the proposed standard may be adopted into state building codes, and as such may have far-reaching effects on building construction and management, especially if Standard 62-1989R is adopted in its present form where its requirements may be applicable to both new and existing buildings. Thus, the proposed standards require the close attention of building owners and designers.

This memorandum is intended only as a general discussion of these issues. It should not be regarded as legal advice. We would be pleased to provide additional details or advice about specific situations if desired.

Margaret Murphy

John L. Opar

Emily Conant



[1]Indoor Air Facts No. 1, EPA and Indoor Air Quality, U.S. Environmental Protection Agency (Dec. 1991).

[2]David M. Governo & Eileen P. Kavanagh, Indoor Environmental Claims: Air Quality, 24 Mealey's Emerging Toxic Torts 22, 28 (Mar. 31, 1997).

[3]ASHRAE 62-1989R §3 (Draft, Aug. 1996).