Ridgid fuel piping installation regulations

[roybarnett]

I have always been told there is a minimum length between the penetration into STP/UDC sump and the first fitting installed in a product pipe run. I just ran into an inspector who mentioned this rule in an underground installation checklist. Is this best practice or manufacturer recommendation? Or both? I do understand the principle behind it as far as doglegs and swing joints. But what is the 48" minimum length rule and where did it stem from? I also would like suggestions as to best practice in a situation where the tank burial depth is deep but the dispensers and vent stack are right next to tank pit. How do I avoid over sloping my product piping? Also Is there a flow issue in this case? The between dispenser runs are laid out at a normal 1/8-1/4" fall toward tanks but the home runs have a drastic slope running into tank sump.
I never see many petroleum construction guys talk on here much? I learned what I know by talking to people who share the same career and passion as I. Feel free to share your knowledge. Somebody out there is thirsty and just might listen.

[CherokeeUST]

Hey Roy,
PEI RP 100, NFPA 30 and API RP1615 are the industry standards. But the catch all phrase EPA uses in their guidance is "Follow manufacturers instructions".

You can access the 2018 version of NFPA 30 for free here. I don't see an installation checklist in it.
http://www.nfpa.org/codes-and-standards ... il?code=30

You can order a copy of the 2017 version of PEI RP 100 here. I have a 2011 version on my desk and there is not any checklist in it.
https://www.pei.org/rp100

You can read API RP1615 online for free. It is hidden in the API website.
This link won’t take you directly to it. http://publications.api.org/marketing.aspx After you "log in" you can read 1615 for free under the "Marketing" category. This publication does have UST checklists as appendices.

[DPittman]

A good question few understand. I'd like to think the old 4' rule is the throwback to the old metal swing joint days when fiberglass pipe was just starting to be used. This reference is only found in the NFPA 30 and probably needs to be updated/removed. The Fiberglass pipe manufacturer does not call for this in their installation recommendation and neither does PEI's PR100. If you are trying to honor NFPA 30 recommendation on this keep in mind they only call for a pipe change in any one direction to be at least 4'. If your pipe is going through a containment sump it only changes direction when it hits a 90-degree elbow.

[roybarnett]

So, I found my answer. It is not mentioned in RP-100 or NFPA 30/A. But is is noted in the API publication 1615 "Installation of Underground Petroleum Storage Systems" document. Specifically 13.7.3 (Fiberglass-reinforced plastic piping). And the way i understood it is that the 4' minimum is used to create a ways for movement of the piping due to settling of soil, natural earth movement, and maybe line shock? API refers to this as a means of creating a semi flexible connector. There was a time in my career that I designed several fuel systems with above ground storage tanks. When I had to change direction of the piping I always created a swing joint. Also in underground storage tank systems that are manifolded together by means of a siphon bar I always use a swing joint to allow sloping of the pipe coming off the high side/motor connection. Anyway just rambling and thrilled that I have a definite answer from the horses mouth. And I will definitely not argue this with an inspector whether he knows the best practice or not!