Risk Management Indoor Air Quality (IAQ) Tailoring Lease Specifications www.saif.com
No representations or recommendations are made by the author(s) or its agents or its employees as to the legal sufficiency, legal effect or tax consequences of the language presented in this paper or the transactions relating thereto.
Each person using these materials should consult their own professional and legal counsel in the use or modification of these materials and must depend upon their own knowledge of the law.
Conditions of inadequate Indoor Air Quality (IAQ) can arise from deficiencies in the design, the installation or the operation of a building and its heating, ventilating and air conditioning (HVAC) systems or simply from overwhelming the design capacities of the system. Lease requirements to assist in protecting IAQ will differ for an initial tenant occupying a new building, as compared with a tenant occupying space with an established prior history. This second case is considered the more typical situation.
Both tenant activities and owners influence indoor air quality. While many of the clauses suggested in this document address the issue from the perspective of the tenant, similar clauses can be suggested from the perspective of the landlord. In particular, it may be desirable for the owner to clearly communicate the design capacities of the HVAC system to the tenant.
Outside Air Distribution
The delivery of sufficient quantities of outdoor air to a building’s occupied spaces can be considered the most important requirement for achieving good IAQ. In the results reported by the National Institute for Occupational Safety and Health (NIOSH) summarizing their investigations of inadequate IAQ, 50 percent of the cases have been attributed to the delivery of insufficient quantities of outdoor air for ventilation.
Different types of heating, ventilating and air conditioning (HVAC) systems are available for providing this crucial requirement. There are decentralizing systems such as perimeter fan/coil units where each through-the-wall unit brings in some outdoor air and heats or cools it as necessary. This approach, however, is not practical for buildings with large interior areas. For these buildings there are the two basic types of centralized systems; constant air volume (CAV) or variable air volume (VAV). In CAV systems, local thermal control is achieved by varying the temperature of the delivered air. In VAV systems, local thermal control is achieved by varying the quantity of cooling air delivered, and possibly the delivery temperature.
For all of these system types, the quantity of ventilation air can vary as a function of the specifics of the system. There are some systems that are designed to only deliver a constant minimum quantity of outdoor air (OA).
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