REG NASA-LLIS-1084--2000 Lessons Learned - Mishap Investigation Board Report Findings for the GSFC Building 24 Pressurized Steam Line Close Call of August 19 1999.pdf

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1、Lessons Learned Entry: 1084Lesson Info:a71 Lesson Number: 1084a71 Lesson Date: 2000-03-24a71 Submitting Organization: GSFCa71 Submitted by: Suzanne Johnson / Eric RaynorSubject: Mishap Investigation Board Report Findings for the GSFC Building 24 Pressurized Steam Line Close Call of August 19, 1999 A

2、bstract: The primary cause of this Central Power Plant (CPP) pressurized steam line incident was that no one took responsibility for coordinating all aspects of executing the outage.Recommendations included revising procedures, conducting an independent safety audit of the CPP, Developing as-built d

3、rawings for the CPP, and establishing “Locked And Tagged Out” processes and requirements.Description of Driving Event: On August 19, 1999, contractors were removing concrete from around steam lines with a jackhammer. These steam lines should have been de-energized prior to commencement of the work b

4、ut one line was found to still be pressurized with 100 psi steam. Background: The pressurized steam line incident occurred in and around Building 24, the Goddard Space Flight Center (GSFC) Central Power Plant (CPP), Steam Manhole (STW # 30 and an excavated hole outside of the north side of the CPP.A

5、 work request (#8002) was submitted in June 1998 to reroute the Condensate and High Pressure Drip (HPD) lines entering Building 24 at the north wall into the blow-down pit. The corrosive atmosphere in the pit was degrading the pipes so plans called for rerouting them above ground and bringing them t

6、hrough the wall above the pit. The plans developed to complete this task would include excavation of the site to expose the lines and the cutting and rerouting of the lines above ground. Detailed drawings and plans for this task were developed and in April 1999 the work commenced. After excavation o

7、f the site, it was discovered that the concrete kicker that held the pipes in place was much larger and closer to the wall than anticipated. This required a Field Change Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Request (#8002-1) to allow for j

8、ackhammer removal of the concrete kicker surrounding the condensate and HPD lines so that the necessary modifications could be made. The Project Manager (PM) for the re-routing project submitted a Utility Outage Request (UOR) to de-energize the condensate, the HPD and the adjoining High Pressure Ste

9、am (BPS) line prior to removal of the concrete. Note that the concrete kicker in question surrounded all three pipes. The contractors never intended to jackhammer the concrete around the HPS line but requested it to be de-energized as a precaution.The UOR submitted for de-energizing the condensate,

10、HPD and BPS line requested the outage for 7:00 a.m. on August 19, 1999 through 3:30 p.m. August 20, 1999. Securing these three lines required actions on the part of the Mechanical Maintenance Shop (MMS) and the CPP. The back of the UOR is the Utility Outage Safe Clearance Plan (UOSCP). One section o

11、f the UOSCP is reserved for the organization with the action to fill out what procedure is necessary to complete the outage. This section for the subject UOSCP was filled out by the MMS supervisor and included a brief statement about what action was necessary by CPP personnel. A CPP representative d

12、id not fill out the CPP procedure portion of the form, despite a note from the MMS supervisor requesting the CPP supervisor to review the section and sign off.The correct method for de-energizing the BPS line consists of closing the appropriate valves in STMH #30 and closing valves #1 through #3. Af

13、ter all valves are closed, the line must be “blown down“, that is, a pressure relief valve should be opened in the blow-down pit to allow the existing steam to escape.Contractor personnel involved in the excavation and pipe re-routing project were the Construction Manager (CM), the Project Manager (

14、PM), and the excavators, jack-hammerers, and pipe fitters. Personnel that were responsible for de-energizing the steam lines being worked on were civil servants from the MMS and the CPP.The following incident description describes the sequence of events that happened August 19, 1999 as best as the M

15、ishap Investigation Board (MIB) could reconstruct from witness testimony. Although many events were described by more than one witness as having occurred, the timeframes and order in which they occurred were often in conflict. The MIB felt that the descriptions of events were more accurate than the

16、times associated with them by individuals memories and therefore based this incident description on the most common version of events.On the morning of August 19, 1999, the contractor began preparations to commence jack-hammering the concrete kicker. Preparations included clearing debris from the ex

17、cavated hole, setting up an air compressor to power the jackhammer and talking with CPP personnel about the UOR. The contractors on-site supervisor and the CPP Maintenance Leader walked around inside the CPP identifying which valves needed to be shut off. Testimony is conflicting on whether or not t

18、hey discussed the need to secure the HPS line at this time.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Around the same time, MMS workers entered STMH #30 and closed, locked and tagged out (LOTO) the appropriate valves. After the valves were secur

19、ed a MMS worker entered the CPP to inform them that the valves under MMS control were closed. While in STMH #30, MMS personnel discovered a leaking valve gasket on the line going from STMH #30 into building 4 that needed repair. This leaking valve gasket had no impact on the section of line being de

20、-energized. MMS personnel then proceeded to STMH # 15 to secure valves so that the gasket could be repaired later in the day. This is a common procedure in the MMS known as a piggy-back job, where the MMS takes advantage of an already existing UOR to complete some of their work.At some time on the m

21、orning of August 19, 1999, the CPP Maintenance Leader, an Operations Leader and a Boiler Operator began the task of closing valves. According to testimony, the Maintenance Leader was leading the task and instructing the Boiler Operator in which valves to close. The condensate and BPD lines were repo

22、rtedly secured without incident. Due to the complexity of the main north header lines, the lack of “as built“ CPP drawings, the lack of a procedure for securing the north side of the CPP and the lack of valve labels, closure of the BPS line required that the personnel involved trace the north header

23、 line down to identify the valves that needed to be closed. The first valve closed was Steam System Valve (SSV)-003. The second valve closed was SSV-0 17.While CPP personnel were in the process of closing the HPS valves, MMS personnel returned to STMH# 30 to replace the leaking valve gasket going in

24、to Bldg 4. They noticed the HPS line was still hot. It should have cooled off by this time if the line had been properly secured in the morning per the UOR. The MMS Shift Leader testified that they also noticed that the subcontractor was jack-hammering at this time. The MMS workers went to the CPP t

25、o investigate. This is believed to have occurred just before 1:00 p.m. In approximately the same time frame, the contractors also noticed that the BPS line seemed hot. They notified the CM, who came to the site to investigate. He also went into the CPP to investigate. Both the MMS workers and the CM

26、 confronted the CPP Maintenance Leader to find out why the HPS line had not been de-energized. When the MMS and CM confronted the CPP Maintenance Leader and he realized the BPS line was still pressurized, he directed the CPP workers to close the third valve, SSV-007. The MMS workers and Boiler Opera

27、tor then entered the blow-down pit in the CPP and set up the blow-down to de-energize the HPS line. Once the blow-down was set, the MMS workers left. The CM also left the CPP and informed the contractor that the line was now secured.Later in the day, CPP personnel noticed that the blow-down was stil

28、l going on after it should have been completed. The CPP Maintenance Leader consulted with the MMS Shift Leader and they concluded that it was likely that one or more of the valves previously closed was leaking through. They suspected valve SSV-0 17 since it had not been replaced during the recent re

29、novations. As it was time for a shift change (approximately 3:00 p.m.), the Maintenance Leader requested that the second shift Operations Leader have one of his workers close the fourth valve, SSV-0 16. The MIB notes that SSV-0 16 is extremely difficult and hazardous to reach and that this fact may

30、have influenced the CPP personnels decision not to attempt to close it earlier.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-It is also documented in the Operations Leaders Log that the first shift Operations Leader asked the second shift Operation

31、s Leader to “chain lock the North Main Header Valve“ (i.e., lock out the valve). The CPP LOTO log does not have an entry for any LOTO on valves for that day, August 19, 1999. This implies that the BPS line valves were not locked or tagged out at the time they were closed. Once these tasks were compl

32、eted and the line was completely blown down, it could be considered de-energized and safe for the contractors to begin jack-hammering concrete.Follow on Events: The MMS Shift Leader realized that the sub-contractors jack-hammering in the vicinity of a pressurized HPS line was a hazardous event and t

33、herefore reported these events to his supervisor. The MMS supervisor reported them to the General Foreman, who is in charge of both the MMS and CPP operations. The General Foreman called a meeting the next day between MMS and CPP personnel involved so that they could determine exactly what happened

34、and how to prevent it from happening in the future. The primary result of that meeting was the establishment of a new policy for future outages involving the MMS and CPP. The new policy calls for a face-to-face meeting between the workers executing the outage to work out what needs to be done and ve

35、rify that it has been done. An action was given to write a Standard Operating Procedure (SOP) documenting that policy. Testimony conflicts as to who actually received that action. The MIB could find no evidence that it had been done. The Board notes that face-to-face meetings did in fact occur betwe

36、en MMS and CPP personnel during this outage; however, these meetings did not prevent the close call from occurring. Therefore, the proposed corrective actions generated by this meeting did not adequately address the cause (s) of the close call.The MMS Shift Leader also contacted the GSFC Safety and

37、Environmental Branch and informed the Occupational Safety and Health (OSH) Manager of the incident. The OSA Manager requested that the MMS Shift Leader write down his recollections of the events. The MMS Shift Leader did this and handed it over to the OSH representative, expecting them to investigat

38、e the incident. Representatives from OSH testified that they decided at this point not to investigate but rather to wait for Code 220 to officially notify them of the close call via a NASA Mishap Report form (1627 form). They wanted to see if a new close call reporting initiative instituted by Code

39、220 would work. A Mishap Report form was not submitted by Code 220, the MMS or the CPP immediately following the incident so nothing was done for approximately 2 months. When Code 205.2 received word that this MIB was being formed to investigate this close call they assisted Code 227 in writing a Mi

40、shap Report form. This form does not accurately reflect the written witness statement previously provided to Code 205.2 nor do the corrective actions listed fully address the incident root causes.Lesson(s) Learned: The primary cause of the pressurized steam line incident was that no one took respons

41、ibility for coordinating all aspects of executing the outage. Each group involved in the outage focused on what they believed to be their role and did not concern themselves with what the other groups were doing. Consequently, issues that required a coordinated effort such as blowing down the de-ene

42、rgized lines or informing the contractor when it was safe to commence work were not adequately addressed. The Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIB believes that if one person/organization had coordinated the entire job, the contractors

43、 would not have started jack-hammering before the steam line was de-energized. A second primary cause of this incident is that is that no procedures exist for shutting down the north High Pressure Steam (HPS) line in the CPP and no prior planning occurred. Workers had to trace the steam line the day

44、 of the outage to determine what valves to close. Their efforts were hindered by such contributing causes as unlabeled valves, no visual pressure indicators on the line, inadequate access to the valves and a leaking valve. This resulted in the line not being completely de-energized until after the c

45、ontractors had completed their shift for the day. Corrective Action Plans from past mishap investigations must be implemented in a timely manner and the actions sustained over time.No clearly identified leader to coordinate all aspects of a task involving multiple organizations can result in a failu

46、re to communicate safety-critical information that could prevent a mishap. Such tasks should have a clearly identified leader who has the responsibility of coordinating all aspects of the job and communicating safety-critical information to all personnel involved in the task.Outdated or inaccurate f

47、acility drawings/documentation and poor labeling of a facility such as the CPP increases the difficulty of accomplishing tasks of all levels of complexity and therefore increases the likelihood of errors and mistakes that could result in a mishap. Accurate and up-to-date drawings/documentation and c

48、lear labeling of such facilities on the other hand, assist workers in understanding the detailed design and operations of the facilities and therefore minimize the likelihood or errors and mistakes.Division safety guidance documents should be reviewed periodically and updated to reflect changes in N

49、ASA/GSFC safety policies, organizational structure or evolved ways of doing business.Recommendation(s): 1. Revise the Code 220 S b) schedule a pre-task meeting between all participants; c) each Code 227 section involved in the outage to provide a detailed description of their portion of the outage procedure and approval signature.2. Conduct an independent safety audit of the CPP. Clearly label all valves in CPP so they are distinguishable from safely accessible area