GSA ​Facilities Standards for the Public Buildings

U. S. General Services Administration Office of the Chief Architect

Facilities Standards (P100) Overview

The Facilities Standards for the Public Buildings Service (P-100) establishes design standards and criteria for new buildings, major and minor alterations, and work in historic structures for the Public Buildings Service (PBS) of the General Services Administration (GSA). This document contains policy and technical criteria to be used in the programming, design, and documentation of GSA buildings.   

The Facilities Standards is a building standard: it is not a guideline, textbook, handbook, training manual, or substitute for the technical competence expected of a design or construction professional.


5.8 HVAC Components

UV-C Emitters / Lamps

UV-C Irradiation: Ultraviolet light (C band) systems must be incorporated in all AHU containing cooling coils. The UV-C lamps must be installed downstream of the coils and above the condensate pans. UV-C systems must be designed for the minimum irradiance required to prevent the growth of microorganisms. Ozone concentrations in the discharge air from the UV-C system must not exceed 50 ppb (see Section 5.3). Systems must be specifically manufactured for this intended use. Safety interlocks must be provided on all access panels/doors. AHUs large enough for personnel entry must contain a provision for the deactivation, isolation, and locking out of the system power source in addition to safety interlocks provided. One or more sight glasses must be located to allow maintenance personnel to safely determine lamp operation. 

Filters and Filter Sections

Air filtration must be provided in every air-handling system. Air-handling units must have a pre-filter and a final filter, each located upstream of the cooling and heating coils. The filter media must be fabricated so that fibrous shedding does not exceed levels prescribed by ASHRAE Standard 52.2-2007. The prefilters must have a MERV of 8, and the final filters must have a MERV of 13, as defined in ASHRAE Standard 52.2-2007. Filter racks must be designed for a maximum bypass leakage air around the filter media of 0.5 percent of the design supply airflow rate. Filters must be sized at 2.5 m/s (500 fpm) maximum face velocity. 

The filter housing and all air-handling components downstream of the filter housing must not be internally lined with fibrous insulation. Double-wall construction or an externally insulated sheet metal housing is permitted. The filter change out pressure drop, not the initial clean filter rating, must be used in determining fan pressure requirements. Differential pressure gauges and sensors must be placed across each filter bank to allow quick and accurate assessment of filter loading as reflected by airpressure loss through the filter, and the sensors must be connected to the BAS. 

Where occupancy requirements or building functions are likely to generate airborne particles, vapors, or gases that result in concentrations exceeding those in Section 5.3, special air filtration or air cleaning components must be provided for the supply and return air, or dedicated and localized exhaust systems must be used to contain these contaminants.