Manually Operated Stop Valves for IM 101 Portable Tanks
Pipeline and Hazardous Materials Safety Administration · Sep 21, 1998 · Reference No. 98-0200
Interprets: 49 CFR § 178.270
This is in response to your letter requesting clarification of the requirements for valves, nozzles, piping, and gauging devices for IM 101 portable tanks in 49 CFR 178.270-12(a). Specifically, you asked if a 24-inch inspection opening, located below the normal liquid level of the tank, is required to be fitted with a manually operated stop valve.
The answer is no. Paragraph (a) requires all tank nozzles, thermometer wells and inspection openings be fitted with manually operated stop valves located as near the shell as practicable either internal or external to the shell. However, the last sentence states, "a tank nozzle installed for a thermometer well or inspection opening need not be provided with a manually operated stop valve."
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.