The battle continues, this time outside process safety! I get these arguments routinely when people inquire if they can use their HHC/EHS as the media for pressure and leak testing. I can only assume that PHMSA is getting pushback by requiring water or other similar viscosity liquid to be used as the test medium.
When hydrostatic pressure tests for cargo tanks are required in part 180, subpart H, the HMR requires that water or other similar viscosity liquid be used as the test medium (see § 180.407(g)(viii)). PHMSA understands that some stakeholders believe the requirement to use water—or other similar viscosity liquid—may be unduly restrictive. PHMSA has authorized the use of alternate test mediums for portable tank testing (e.g., DOT SP–20294, 20308, and 16163), but has not authorized this for cargo tanks. PHMSA requests comment on the following questions to evaluate authorizing additional liquids for hydrostatic testing cargo tanks:
- Are there other liquids that may be safely and effectively used to hydrostatically test cargo tanks? Explain.
- For any liquid(s) identified, what advantages does the material provide compared to water or a similar viscosity liquid? Discuss at least the economic, environmental, and safety advantages of the alternative material.
- Do you support authorization to use a material other than water or a similar viscosity liquid for cargo tank hydrostatic tests? Explain.
- Are there situations where the use of water was not suitable for a CTMV pressure test? If so, why?
- Is it cost effective or beneficial to authorize alternative liquids to be used in limited applications for testing and inspecting of DOT specification cargo tanks used to transport specific types of hazardous material?