The debate rages on in process safety circles as to how one can "pressure test" their piping that was installed using ASME B31 series of RAGAGEPs.  It has always been "the rule" that we use the hydrostatic method UNLESS this method would cause a hazard or purity concern; however, as with most practices we have come to find this no longer "the rule" but rather "an option" and I beg to differ and the IFC and ASME tend to agree with me when it comes to existing piping.  Why is this just now an issue with existing piping?  Simply, businesses are just now getting around to ensuring their process "complies with recognized and generally accepted good engineering practices".  Yes, over 25 years later, PSM/RMP facilities are just getting around to "pressure testing" their piping and this "existing piping" has some special restrictions on how it can be "pressure tested"...

The International Fire Code, of which many states have adopted a revised version, states the following in regards to flammable/combustible liquids piping, specifically "existing piping":

3403.6.3 Testing. Unless tested in accordance with the applicable section of ASME B31.9, piping, before being covered, enclosed or placed in use, shall be hydrostatically tested to 150 percent of the maximum anticipated pressure of the system, or pneumatically tested to 110 percent of the maximum anticipated pressure of the system, but not less than 5 pounds per square inch gauge (psig) (34.47 kPa) at the highest point of the system. This test shall be maintained for a sufficient time period to complete visual inspection of joints and connections. For a minimum of 10 minutes, there shall be no leakage or permanent distortion. Care shall be exercised to ensure that these pressures are not applied to vented storage tanks. Such storage tanks shall be tested independently from the piping.

3403.6.3.1 Existing piping. Existing piping shall be tested in accordance with this section when the fire code official has reasonable cause to believe that a leak exists. Piping that could contain flammable or combustible liquids shall not be tested pneumatically. Such tests shall be at the expense of the owner or operator.

Exception: Vapor-recovery piping is allowed to be tested using an inert gas.

This "existing piping" requirement would apply to piping that was NEVER pressure tested when it was installed AND on piping that was tested when it was installed but has not been opened for maintenance purposes and needs to be tested BEFORE it is placed back into service.  We see a lot of piping each year that was installed but the facility can not state what code it was installed to and thus most of the piping has never been tested (neither pressure or leak testing per a RAGAGEP).  We also have seen flammable liquid piping that was installed with the intent it would "never be a PSM process" and thus the facility thought it got a "pass" from installing the piping per some RAGAGEP - NOTHING could be further from the truth, but it is a common misconception.  But now the process is being expanded and will now become a PSM covered process, thus the "existing piping" that was never pressure or leak tested per ASME B31.3 will now have to be tested and 3403.6.3.1 Existing piping will come into play.

The video of the week this week shows us as to why the code(s) prohibit us from pneumatically testing pipe we may have a serious question regarding its integrity.  A pipe that already has as reasonable cause to believe that a leak exists has essentially lost its intended integrity already and loading it up with a pressurized gas could end really badly!  

Pneumatic testing may be easier and more convenient, but it brings with it significant hazards as show in this weeks Video of the Week.

 
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