| (iii) Areas requiring fully ducted systems. Fully ducted supply, return and exhaust air for HVAC systems shall be provided for all critical care areas, sensitive care areas, all patient care areas, all areas requiring a sterile regimen, clean storage rooms, and where required for fire safety purposes. Combination systems, utilizing both ducts and plenums for movement of air in these areas, shall not be permitted. Ductwork access panels shall be labeled. (iv) Temperatures and humidities. The designed capacity of the systems shall be capable of providing the ranges of temperatures and humidities as shown in Table 1 of §135.56(a) of this title. (v) Thermometers and humidity gauges. Each operating room, special procedure room, and postoperative recovery suite shall have temperature and humidity indicating devices mounted at eye level. (vi) Outside air intake locations. (I) Outside air intakes shall be located at least 25 feet from exhaust outlets of ventilating systems, combustion equipment stacks, medical-surgical vacuum system outlets, plumbing vents, or areas which may collect vehicular exhaust or other noxious fumes. (Prevailing winds and proximity to other structures may require other arrangements). (II) Plumbing and vacuum vents that terminate five feet above the level of the top of the air intake may be located as close as 10 feet to the air intake. (III) The bottom of outside air intakes serving central systems shall be located as high as practical but at least six feet above ground level, or if installed above the roof, three feet above the roof level. (vii) Contaminated air exhaust outlets. Exhaust outlets from areas (laboratory hoods, etc.) that exhaust contaminated air shall be above the roof and be arranged to exhaust upward unless the air has been treated by an appropriate means where sidewall exhaust will be allowed. Exhaust outlets from areas containing ethylene oxide sterilizers and other contaminants, e.g., glutaraldehyde, shall terminate not less than eight feet above the roof level (or be appropriately labeled as "hazardous exhaust") and arranged to exhaust upward. (viii) Directional air flow. Ventilation systems shall be designed and balanced to provide pressure relationships contained in Table 1 of §135.56(a) of this title. For reductions and shut down of ventilation systems when a room is unoccupied, the provisions in Note 4 of Table 1 of §135.56(a) of this title shall be followed. (ix) Air distribution devices. Design shall consider turbulence and other factors of air movement to minimize airborne particulate matter. Where extraordinary procedures require special designs, the installation shall be reviewed on a case-by-case basis. (I) All supply diffusers grilles shall be located on the ceiling or on a wall near the ceiling. (II) Air supply for the operating rooms and special procedure rooms shall be from ceiling outlets near the center of the work area to efficiently control air movement. (III) A minimum of two return air inlets located diagonally opposite from one another and near floor level shall be provided. Bottoms of return air grilles in operating rooms and other anesthetizing locations shall be located not more than 12 inches above the finished floor nor less than six inches above the finished floor. (x) Ventilation start-up requirements. Air handling systems shall not be started or operated without the filters installed in place. This includes the 90% and 99.97% efficiency filters where required. This includes during construction operations. Ducts shall be cleaned thoroughly and throughout by a National Air Duct Cleaners Association (NADCA) certified air duct cleaning contractor when the air handling systems have been operating without the required filters in place. When ducts are determined to be dirty or dusty, the department shall require a written report assuring cleanliness of duct and clean air quality. (xi) Humidifier location. When duct humidifiers are located upstream of the final filters, they shall be located at least 15 feet from the filters. Duct work with duct-mounted humidifiers shall be provided with a means of removing water accumulation. An adjustable high-limit humidistat shall be located downstream of the humidifier to reduce the potential of condensation inside the duct. All duct takeoffs shall be sufficiently downstream of the humidifier to ensure complete moisture absorption. Reservoir-type water spray or evaporative pan humidifiers shall not be used. (xii) Filtration requirements. All air handling units shall be equipped with filters having efficiencies equal to, or greater than, those specified in Table 2 of §135.56(b) of this title. Filter efficiencies shall be average dust spot efficiencies tested in accordance with American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), Inc., Standard 52.2, 1999 edition, Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size. All joints between filter segments, and between filter segments and the enclosing ductwork, shall have gaskets and seals to provide a positive seal against air leakage. Air handlers serving more than one room shall be considered as central air handlers. All documents published by ASHRAE as referenced in this section may be obtained by writing or calling the ASHRAE, Inc. at the following address or telephone number: ASHRAE, 1791 Tullie Circle, Northeast, Atlanta, Georgia 30329; telephone (404) 636-8400. (I) Filtration requirements for air handling units serving single rooms requiring asepsis control. Dedicated air handlers serving only one room where asepsis control is required, such as, but not limited to, operating rooms, special procedure rooms, and treatment rooms shall be equipped with filters having efficiencies equal to, or greater than, those specified for patient care areas in Table 2 of §135.56(b) of this title. (II) Filtration requirements for air handling units serving other single rooms. Dedicated air handlers serving all other single rooms shall be equipped with nominal filters installed at the return air system. (III) Location of multiple filters. Where two filter beds are required by Table 2 of §135.56(b) of this title, filter bed number one shall be located upstream of the air conditioning equipment, and filter bed number two shall be downstream of the supply air blowers, cooling and heating coils. (IV) Location of single filters. Where only one filter bed is required by Table 2 of §135.56(b) of this title, it shall be located upstream of the supply fan. Filter frames shall be durable and constructed to provide an airtight fit with the enclosing ductwork. (V) Pressure monitoring devices. A manometer or draft gauge shall be installed across each filter bed having a required efficiency of 75% or more, including laboratory hoods requiring high efficiency particulate air (HEPA) filters. The pressure monitoring device shall be mounted below the ceiling line within the ASC such that it can be observed by staff. (D) Thermal and acoustical insulation for air handling systems. Asbestos containing insulation materials shall not be used. (i) Thermal duct insulation. Air ducts and casings with outside surface temperature below the ambient dew point or temperature above 80 degrees Fahrenheit shall be provided with thermal insulation. (ii) Insulation in air plenums and ducts. When installed, linings in air ducts and equipment shall meet the Erosion Test Method described in Underwriters Laboratories (UL), Standard 181, relating to Factory-Made Duct Materials and Air Duct Connectors, April 4, 1996 edition. This document may be obtained from the Underwriters Laboratories, 333 Pfingsten Road, Northbrook, Illinois 60062-2096. (iii) Insulation flame spread and smoke developed ratings. Interior and exterior insulation, including finishes and adhesives on the exterior surfaces of ducts and equipment, shall have a flame spread rating of 25 or less and a smoke developed rating of 50 or less as required by NFPA 90A, Chapters 4 and 5 and as determined by an independent testing laboratory in accordance with NFPA 255, A Standard Method of Test of Surface Burning Characteristics of Building Materials, 2000 Edition. (iv) Linings and acoustical traps. Duct lining and acoustical traps exposed to air movement shall not be used in ducts serving critical care areas. This requirement shall not apply to mixing boxes and acoustical traps that have approved nonabrasive coverings over such linings. (v) Frangible insulation. Insulation of soft and spray-on types shall not be used where it is subject to air currents or mechanical erosion or where loose particles may create a maintenance problem or occupant discomfort. (vi) Existing duct linings. Internal linings shall not be used in ducts, terminal boxes, or other air system components supplying operating rooms and the postoperative recovery suite, unless terminal filters of at least 90% efficiency are installed downstream of linings. Cont'd... |
