ESH DocDB Document 3072-v1
Pressure Relief Valve Incident at Proton Assembly Building PAB 5/5/2015
- Public document
- An employee was calibrating a high pressure relief valve for another division. The relief valve was mounted to the high pressure test vessel in the Proton Assembly Building Calibration shop with two reducing bushings (1x3/4 and 3/4x1/2) made of stainless steel. The test pressure was brought up to 1650psig, at which time the relief valve began to chatter rapidly, approximately 5 times, before it propelled upwards towards the corrugated metal ceiling. The relief valve dented the ceiling and fell, contacting the employee in the back of the head. The contact with the 4.42 lb. (approx. 9x4) relief valve caused a contusion and laceration requiring four sutures. The employee was standing approximately 3 feet away from the relief valve and wearing noise reducing ear muffs and prescription safety glasses. The employee secured the gas panel and cylinder, notated what occurred and went to medical.
The initial investigation team included the mechanical subcommittee chairman and the safety chairman from the group and others:
1. The Calibration Shop gas panels used for pressure testing has undergone an engineering review in 1994, there are flow schematics for the operation and procedures for operating the system. All components, upon inspection, appear to be properly rated for the test pressures.
2. The employee conducts high pressure tests (>1000 psig) approximately three times per year. All tests are well documented. (not sure who or where else these are done yet)
3. The threads of the ¾x ½ reducing bushing appear to be compromised either due to use, installation or the incident. The bushings were stainless steel.
4. The ¾x ½ bushing appears to only have been engaged in the 1x ¾ bushing by three threads.
5. The relief valve chattered loudly and vigorously before propelling away from the high pressure test vessel.
6. The test vessel is a code stamped pressure vessel, but is not considered a pressure vessel according to the Labs safety manual due to its size.
7. The calibration test stand has been tagged out until an engineer can verify that the system is sound and documented appropriately. The investigation is ongoing. We are looking at the threads of the compromised pipe reducer under a microscope to see if there are any other clues to the failure. The Mechanical Safety Subcommittee is involved in the HPI investigation. Potential collateral injury: an employee was holding a fan motor on the PAB mezzanine directly above the Calibration Shop. When the relief valve contacted the ceiling/floor he was standing on, he reacted causing slight pain in his neck. He reported to medical as a report only. Medical will monitor for any issues.
- Files in Document:
- Bob Barger email with some thoughts with respect to chattering (incident incidentals.pdf, 30.9 kB)
- Braided high pressure hose test report (hose test rpt.pdf, 101.7 kB)
- CHL Cryogenic Relief Testing Cart Flow Schematic (pressure relief testing cart.pdf, 172.6 kB)
- CHL Cryogenic Relief Testing Cart Instructions (Relief Test Cart Procedure.pdf, 95.3 kB)
- CHL Cryogenic Relief Testing Cart Procedure (ADDP-CH-1002 rev 1.pdf, 366.0 kB)
- List of high pressure tests compiled by Bob Barger for 2013-2015 (HP_Tests_2013-2015.pdf, 105.9 kB)
- Minute from Pete Simon interview (Pete_Simon.docx, 16.1 kB)
- Minutes from 1st committee meeting 5-7-2015 (High Pressure Relief Valve Incident at PAB.docx, 14.5 kB)
- Minutes from Bob Barger interview 5-11-15 (Bob_Barger_interview_notes_5_11_15.docx, 16.5 kB)
- Minutes from Ken Oleson interview (Ken_Olesen_interview_notes_5_12_15.docx, 16.1 kB)
- Minutes from Randy Ward interview (Randy_Ward_interview_notes_5_12_15.docx, 17.3 kB)
- Minutes from Skyler Sherwin interview (Skyler_Sherwin.docx, 15.9 kB)
- Minutes from Terry Anderson interview (Terry_Anderson.docx, 15.6 kB)
- Pages from ASME B1.20.1 pipe thread code (Pages from B1-20-1_2013.pdf, 159.9 kB)
- Pressure Relief Valve Panel Flow Schematic (MD-194470_revB.pdf, 86.5 kB)
- Pressure Relief Valve Panel Pressure Test (Panel_PTest_920622.pdf, 673.0 kB)
- Pressure Relief Valve Panel Relief Valve Sizing Note (Rlf vlv szg 920622.pdf, 115.1 kB)
- Pressure Relief Valve Panel System Review 1992 (Panel_Sys_Rev_920805.pdf, 544.1 kB)
- Pressure Relief Valve Panel System Test Procedure 1992 (panel test proc.pdf, 264.8 kB)
- Procedure for calibrating the incident relief valve (Type 83_proc.pdf, 529.8 kB)
- Test sheet for valve completed the day prior to the incident (AG_81SF46-4_11-28736_1639_150505.docx, 16.8 kB)
- Other Files:
- 1"x 3/4" bushing secured to High Pressure Test Vessel (IMG_4167.jpg, 105.1 kB)
- 1"x 3/4" bushing secured to High Pressure Test Vessel 2 (IMG_4170.jpg, 70.4 kB)
- CHL PRV Test Panel (IMG_4212.JPG, 111.2 kB)
- CHL PRV Test Panel 2 (IMG_4213.JPG, 130.0 kB)
- CHL PRV Test Panel 3 (IMG_4214.JPG, 105.3 kB)
- CHL PRV Test Panel 4 (IMG_4215.JPG, 146.2 kB)
- Close up of thread damage (Close up of thread damage.jpg, 70.3 kB)
- Close up of thread damage 2 (Close up of thread damage 2.jpg, 62.9 kB)
- Close up of threads of 3/4"x1/2" SS bushing (Close up of threads.jpg, 492.8 kB)
- Close up of threads of 3/4"x1/2" SS bushing 2 (Close up of threads 2.jpg, 495.8 kB)
- High Pressure Relief Valve and Low Pressure Relief Valve Vessels (CIMG6480.JPG, 2.2 MB)
- High Pressure Test Volume Vessel Code Stamp (CIMG6479.JPG, 2.1 MB)
- High Pressure Testing Vessel Thread photo (CIMG6481.JPG, 2.2 MB)
- High pressure and low pressure vessel setup (IMG_4175.jpg, 140.8 kB)
- High pressure and low pressure vessel setup close up (IMG_4176.jpg, 134.1 kB)
- IB-1 Pressure Relief Valve Test Panel Photo (IB-1 pressure relief valve test panel.JPG, 100.9 kB)
- Impact at ceiling (IMG_4166.jpg, 30.8 kB)
- PRV position after incident (IMG_4163.jpg, 46.2 kB)
- Position of worker in relation to pressure relief valve at time of incident (IMG_4174.jpg, 131.6 kB)
- Valve position after incident (IMG_4164.jpg, 39.3 kB)
- Valve position after incident 2 (IMG_4165.jpg, 35.8 kB)