20070404 Sewer Cmt 1 03092009
The Yelm Sewer Department agrees with and supports the requirement that STEP tank sizing for the 10,500 ft2 Retail building and the 7,880 ft2 Retail building go through another review
process once occupancy and uses are known. The need for Grease Interceptors was not addressed in this review and prior to the acceptance of the retail bldg STEP system acceptance, uses
will need to be defined.
The Sewer Department requires transfer switches and 24 hours of storage volume except in cases where the building will be provided with a dedicated automatic
back up generator connected to the STEP system.
The Yelm Sewer Dept. is requiring any tanks greater than 6000 gallons to be split into a holding tank and a pump tank. A 6000 gallon
tank can be pumped by two Septage trucks, while an 8000 gallon tank will require two trucks and a trailer and is more of a logistical issue. The sewer dept. ends up dealing with more
run-in with the larger tanks. This is supported in Paragraph C1-10.1.6 A on page C1-31 of the orange book.
The 10,000ft2 building, with 24 hours of storage, requires over 8000 gallons
of storage. We suggest a 6000 gallon holding and a 3000 baffled pump tank?
The 7,880 ft2 building requires 6039 gallons of Capacity by our calcs so 6000 gallon tank works, again subject
to re-review with uses.
The Furniture Store 3000 gallon tank looks good.
3000 gallon tank will not need dead-man anchor System.
The Sewer Dept. will need complete submittals on all tanks
and appurtenances prior to approval for construction.
Prior to Construction, Contractor to check sewer spec. addendum to yelm development guidelines, available through the city website.
Please
show pipe size of side sewers.
Please show depth of bury of tanks. Invert elevation to be less than 5 feet to grade.
Sewer inspections require 48 hour notice. Sheet #11 note 20 is wrong.
The
position of the 6000 gallon tank would require blocking all access to that parking lot for the duration of tank maintenance and pumping.