HomeMy WebLinkAboutMinor Mod Scope Letter 8-12-16From: ROBERT RIESS [mal1to:RRIESS0penvres.o
Sent.- Wednesday, May 11, 2016 11:45 AM
To: Herrera, Gabriel@Waterboards
SubjecLo Transition sump question
Hey Gabriel,
For new UST construction, can the vapor/vent line transition occur above grade, so that they do not have to install a double walled (interstitially
monitored) transition sump?
Would they have to monitor an above grade sump (in any way) if a vent/vapor transition occurs inside it?
ex: an underground double walled VPH vapor piping exits above grade, the VPH piping enters the single walled sump (that is above grade and sittir
on concrete/asphalt) where the transition to the single walled vent piping occurs and exits the above grade sump.
Robert RieB
Stanislaus County Department of Environmental Resources
Hazardous Materials Division
3800 Cornucopia Way, Suite C
Modesto, CA 95358
209.525.6749
rriessO
Mvres.orq
Robert
That could work.
All piping installed on USTs installed after January 1, 1991 has required to have an approval from an independent testing organization (U L is one of
those organizations). The appropriate UL listing for fiberglass pipe (U L971) is for underground pipe(not exposed to sunlight). As soon as it daylights
the U L listing no longer applies and cannot be used. That is where the transition box would be necessary. The fiberglass pipe can connect above
grade in the transition box where the fiberglass pipe is isolated from daylight and steel pipe can continue out of the box. The secondary
containment and interstitial monitoring of the pipe through the use of vacuum, pressure, or hydrostatic fluid (VPH) is required only to grade and
could terminate in the transition box above grade. The box then would not be subject to VPH monitoring.
As far as whether the box would need a sensor or not I think would depend on how the site in monitored/managed. The piping in the box, while
above grade, is still piping connected to a UST and should be regulated. The two basic forms of monitoring are visual and non-visual
monitoring. The route of visual monitoring requires an inspection through direct viewing (a non —obstructed daily viewing with a log kept). Non-
visual monitoring is used when visual monitoring is not feasible. So I would say a sensor should be used in the box if a periodic inspection through
direct viewing is not or cannot be performed as part of the monitoring plan.
I can't think of a place anywhere on a UST, above grade portions or below grade portions, where product could accumulate without there being a
sensor located in that location or a periodic visual inspection occurring in that area.
Feel free to inquire further if necessary.
CORY HOOTMAN, PX.
STATE WATER RESOURCES CONTROL BOARD
UNDERGROUND STORAGE TANK LEAK PREVEN-nON UNrr
10301 1 STREET, 15-w FLOOR
SACRAMENTO, CA 95814
PH: (916) 341-5666