I see many contractors still arguing that Pressure Testing and Leak Testing are the same test. This is incorrect, as I have often discussed in my ramblings on this website. This post breaks down the requirements of the most common “leak test,” called the “bubble test.” ASME B31.3 refers us to ASME BPVC Section V for guidance on performing the “bubble test” on our piping. And yes, we are well aware that ASME Section V is a pressure vessel code; however, rather than copy and paste the requirements from Section V, the B31 series refers us to Section V. The bubble test practice is the same whether we are looking for leaks on a weld on a pressure vessel or pressurized piping.
Please note that this post goes back to our Pre-Start Up Safety Review line item, which so many sign off on without fully understanding what they are signing off on!
1910.119(i) Pre-startup safety review.
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The pre-startup safety review shall confirm that prior to the introduction of highly hazardous chemicals to a process:
1910.119(i)(2)(i) Construction and equipment is in accordance with design specifications;
68.77 Pre-startup review
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(b) The pre-startup safety review shall confirm that prior to the introduction of regulated substances to a process:
(1) Construction and equipment is in accordance with design specifications;
(emphasis by me)
MANDATORY APPENDIX I BUBBLE TEST — DIRECT PRESSURE TECHNIQUE
I-1010 SCOPE
The objective of the direct pressure technique of bubble leak testing is to locate leaks in a pressurized component by the application of a solution or by immersion in liquid that will form bubbles as leakage gas passes through it.
I-1020 GENERAL
I-1021 WRITTEN PROCEDURE REQUIREMENTS I-1021.1 Requirements. The requirements of T-1021.1, Table I-1021, and the following as specified in this Article or referencing Code shall apply. (a) soak time (b) pressure gage (c) test pressure (d) acceptance criteria I-1021.2 Procedure Qualification. The requirements of T-1021.3 and Table I-1021 shall apply.
I-1031 GASES
Unless otherwise specified, the test gas will normally be air; however, inert gases may be used.
NOTE: When inert gas is used, safety aspects of oxygen deficient atmosphere should be considered.
I-1032 BUBBLE SOLUTION (a) The bubble forming solution shall produce a film that does not break away from the area to be tested, and the bubbles formed shall not break rapidly due to air drying or low surface tension. Household soap or detergents are not permitted as substitutes for bubble testing solutions. (b) The bubble forming solution shall be compatible with the temperature of the test conditions. I-1033 IMMERSION BATH (a) Water or another compatible solution shall be used for the bath. (b) The immersion solution shall be compatible with the temperature of the test conditions.
I-1072 SURFACE TEMPERATURE
As a standard technique, the temperature of the surface of the part to be examined shall not be below 40°F (5°C) nor above 125°F (50°C) throughout the examination. Local heating or cooling is permitted provided temperatures remain within the range of 40°F (5°C) to 125°F (50°C) during examination. Where it is impractical to comply with the foregoing temperature limitations, other temperatures may be used provided that the procedure is demonstrated.
I-1073 APPLICATION OF SOLUTION The bubble forming solution shall be applied to the surface to be tested by flowing, spraying, or brushing the solution over the examination area. The number of bubbles produced in the solution by application should be minimized to reduce the problem of masking bubbles caused by leakage.
I-1075 LIGHTING AND VISUAL AIDS
When performing the test, the requirements of Article 9, T-952 and T-953 shall apply.
I-1076 INDICATION OF LEAKAGE
The presence of continuous bubble growth on the surface of the material indicates leakage through an orifice passage(s) in the region under examination.
I-1077 POSTTEST CLEANING After testing, surface cleaning may be required for product serviceability.
I-1081 LEAKAGE
Unless otherwise specified by the referencing Code Section, the area under test is acceptable when no continuous bubble formation is observed.
I-1082 REPAIR/RETEST
When leakage is observed, the location of the leak(s) shall be marked. The component shall then be depressurized, and the leak(s) repaired as required by the referencing Code Section. After repairs have been made, the repaired area or areas shall be retested in accordance with the requirements of this Appendix.