WAC 296-150V-1590
What requirements apply to waste holding
tanks for conversion vendor units? Conversion vendor units may use
either portable waste holding tanks approved by the department of
health or permanently mounted waste holding tanks.
(1) All portable waste holding tanks must be listed for the
intended use and used per their listing.
(2) All permanently mounted waste holding tanks must meet the
following specifications:
(a) Tanks must be listed for the intended use, installed per
their listing, and be securely installed to prevent displacement
during transportation;
(b) Tanks must be easily removable for service, repair or
replacement without having to remove any permanent construction;
(c) Neither the inlet nor vent fitting may extend downward
into the tank more than 1-1/2 inches;
(d) The drain opening must be located at the lowest point of
the tank;
(e) Tanks must be vented at the highest point in the top of
the tank by one of the following methods:
(i) A 1-1/4 inch diameter vent pipe;
(ii) A continuous vent serving as a drain from one additional
fixture provided the drain portion is increased one pipe size
larger than the connected trap arm;
(iii) Two or more vented drains when at least one is
wet-vented and each drain is separately connected to the top of the
tank;
(f) A fullway termination valve must be installed in the tank;
and
(g) No drain connection may be made between liquid and body
waste holding tanks upstream of fullway termination valves.
[Statutory Authority: Chapter 43.22 RCW. 99-18-069, §
296-150V-1590, filed 8/31/99, effective 10/1/99.]