09-02
per bed. Size holding tank for the ambulatory care center or research building on 4 L/m2 (0.1 gallons
per square foot). Provide method of blocking flow downstream from each tank if sewer should rupture
downstream and sewage discharges on grade. Design top of tank to be below building floor to prevent
backflow into the building. Provide tank with 900 mm (36 inch) manhole access. Maintain a minimum
sewage flow velocity of 600 mm (two feet) per second. Include all provisions necessary to facilitate the
choice of one or a combination of the following sewage disposal operations:
3.6.1.1 Daily removal of all contents by a commercial septic tank cleaner.
3.6.1.2 Daily removal of all contents by a portable pump discharging to an intact off-site sanitary
sewer.
3.6.1.3 Daily removal of liquid contents by gravity flow, or by a portable pump discharging to an on-
site emergency leaching basin constructed after an earthquake.
3.6.1.3.1 Using a commercial septic tank cleaner, remove accumulated sludge following a 4-day
operating period of liquid sewage disposal.
3.6.1.3.2 Manually apply powdered chlorine to disinfect liquid sewage before discharging to a leaching
basin.
3.6.2 Hurricane and Major Flood Areas. Sanitary sewage holding tanks are not necessary.
3.7 Natural Gas Service
3.7.1 Earthquake Areas. In addition to a manual shut-off valve, provide an earthquake sensitive
automatic safety shut-off valve in the on-site gas supply line serving the medical center or ambulatory
care center. If gas is the normal fuel for the boiler plant, provide a minimum of 10-days non-emergency
supply of fuel oil in on-site storage tanks. Design a safe and reliable means of ready access for
maintenance and operation of the emergency fuel oil storage tanks.
3.7.2 Hurricane and Major Flood Areas. No additional requirements above that required in VA
Design Manuals.
3.8 Steam Service
3.8.1 Earthquake Areas. Do not purchase the steam supply in whole or part from an off-site or non-
VA owned facility. Provide an on-site boiler plant either contiguous or close to the hospital and
research buildings or ambulatory care center and above the 100 year flood plain. Design the boiler
plant and its emergency fuel oil storage facilities to resist the same seismic forces as the hospital or
ambulatory care building. If local code is more stringent, comply with local code.
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