UFC 3-420-01
25 October 2004
Including changes 1 and 2, October 2006
The deep seal trap is provided to reduce the problem of the unused trap drying
out and allowing the back flow of sewer gases, fumes, and vermin into the space.
Weekly testing of the EWS will be usage enough to refill the trap seal; otherwise,
provide an automatic trap priming valve connected to the cold water supply to
maintain the trap seal.
d. Piped drains, where provided, should connect to drain as follows:
1) Extraordinary hazard materials - such as poisons, should not discharge into
a drain system. Utilize the HAZMAT spill containment curb system to contain the
EWS water flow. Provide remote alarm reporting to a central manned station.
Immediate action is required to prevent poison contaminated water from spreading
throughout the facility.
The piped drain is omitted to prevent inadvertent exposure of persons
downstream of the piped drain from unknowingly contacting the potentially
poisonous runoff. The hazardous material spill response team answering
the alarm will be aware of the hazards and capable of taking appropriate
measures for self-protection. If the HAZMAT spill containment curbed area
has insufficient volume to hold a minimum of 30 minutes of EWS water
flow, provide a piped drain to an above ground holding tank sized to hold at
least 30 minutes of flow. Properly label the piping and the tank as holding
poisonous fluids. Provide a HAZMAT spill containment berm around the
holding tank.
2) Plating shops - Drain to the proper industrial waste treatment system.
Segregate cyanide wastes, including EWS drainage, from all acid wastes.
Segregate hexavalent chromium wastes, including EWS drainage, from all caustics
and cyanides. Where the EWS is located in a multiple use area, such as a material
handling or shipping/receiving area, drain to the proper industrial waste treatment
system.
3) Battery rooms or shops - Drain to the proper neutralization tank, if provided;
otherwise, drain to the sanitary sewer system. Segregate caustics from the Nickel-
Cadmium-Alkali battery area, including EWS drainage, from acids. Segregate acids
from the Lead- Acid battery area, including EWS drainage, from caustics. Do not
allow mixing of acid and alkali wastes in the drains.
4) Oily Waste shops - Drain to the oil/water separator, if provided; otherwise,
drain to the sanitary sewer system. Typical oily waste shops include the following:
paint shops and hangers, paint mix rooms, paint equipment rooms, engine shops,
ground support equipment shops, refueler shops, Public Works automotive shops,
locomotive and crane shops.
5) Miscellaneous materials - Drain to the sanitary sewer system.
6) Exterior EWS in HAZMAT areas - Slope impervious-surfaced grade to drain
D-5
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