16 Construction/Start-Up Phase

Transcription

1 16 Construction/Start-Up Phase An Illustration of the Checklist Analysis and Safety Review Methods 16.1 Problem Definition Background It is the third year of ABC's project and they are finishing their world-scale plant in Anywhere, U.S.A Most of the plant's major equipment has been installed. As the work progresses, ABC's general contractor inspects the site and equipment installations to ensure the work is completed according to the contract. The plant is only a few months away from its targeted start-up date. ABC wants the plant to start up safely and on time. lb help ensure this, ABC's business team asks their process hazards analysis group to perform a HAZOP Analysis of the plant's construction. Mr. Dennis, of ABC's process hazards analysis group, believes that a HAZOP Analysis of the construction is inappropriate, but he does think it is a good idea to review or audit the facility (1) to ensure it is built according to design and (2) to identify any additional safety concerns that may have been overlooked in previous HE studies. Therefore, he suggests a person from the engineering department perform this HE study using a combination of the Checklist Analysis and Safety Review techniques. This person must be experienced with plant construction and start-up to effectively perform the audit. The business team contacts the ABC engineering department with their request for an experienced start-up engineer to perform a Checklist Analysis/Safety Review of the VCM plant., a 15-year veteran of ABC, is selected. has participated in three plant start-ups (two with ABC) and is thoroughly familiar with ABC's design codes and standards. He will use a checklist to help him identify potential safety concerns, not just to verify that as-built equipment complies with ABC's standards. He will also tour the entire site as part of a Safety Review to identify safety concerns. Available Resources A great deal of information exists on the plant. This information includes: PFDs and P&IDs Construction drawings Operating procedures R&D reports Plot plans Equipment specifications Wiring diagrams Previous HE studies

2 briefly scans through this information to see what will be most useful. He reviews the PFDs, plot plans, and process descriptions to gain a general understanding of the plant and VCM production technology. He also reviews MSDSs and previous HE studies to gain an understanding of the material hazards, the process hazards the team identified, the action items, and the resolution of these items. However, the most useful information is the P&IDs, the construction drawings, and the equipment specifications. plans to use this information extensively while actually performing the HE study. During his preliminary review, notes that ethylene is used in the VCM process. While he is familiar with the types of equipment that will handle ethylene (pumps, piping, instruments, etc.), he is unfamiliar with the physical and chemical properties of ethylene. He suggests that ABC have a different person review the plant areas that involve the handling of the ethylene feed material. Selection of Hazard Evaluation Technique The purpose of performing a hazard evaluation at this phase of the project is to verify that the plant is built as designed, that it is built according to accepted construction industry practices, and that safety hazards have not been overlooked. The VCM plant design has already been reviewed several times using a variety of HE techniques and, according to Mr. Dennis, should be safe. However, ABC wants to ensure that the VCM design the HE teams recommended is actually built according to specification and that additional safety hazards have not been created or overlooked. In compliance with Mr. Dennis's recommendation, will use the Checklist Analysis method to perform this HE study. ABC has built many plants and through the course of these construction projects has developed many checklists to audit the facility's construction. These checklists are based on company design standards and experience gained from reviewing mistakes, incident reports, and insights from past HE studies. In addition, will perform a Safety Review of the construction site. In this audit, he will rely on his construction and start-up experience to help him identify unsafe construction practices and determine whether the process is ready to begin start-up testing. Study Preparation The Checklist Analysis/Safety Review will be performed primarily by Mr. Buildit. In preparation for this work, gathers together the checklists ABC has for construction and start-up. These checklists include generic field inspection items for fired heaters, pumps, fans, piping, vessels, columns, valves, and so forth. All of these checklists are available from ABC's Engineering Division. Next, spends several days reviewing the construction drawings of the VCM plant. During this review he uses the checklists to help him prepare specific questions concerning the materials of construction, installation, and testing of various equipment. He notes these questions on the construction drawings he will use during the on-site review. Finally, schedules a visit to the Anywhere site with ABC's construction manager. He provides the manager with a list of areas he will review

3 and a schedule for examining each area. He asks that both ABC and contractor personnel from each area be available to answer questions during the visit. In particular, will need to talk with: Construction Engineer Electrician Site Inspector The contractor's engineer responsible for the installation of the equipment being examined The contractor's supervisor responsible for electrical equipment and wiring in the areas being examined The contractor and/or ABC employee responsible for verifying that the equipment being examined is properly installed He estimates that he will not spend more than an hour per equipment item with these people, and states that he prefers to meet with them as a group Analysis Description arrives at the Anywhere plant at 7:30 Monday morning to begin his review. He meets with Mr. Star, ABC's manager for this project, to discuss the purpose and activities that will take place during his one-week visit. points out that the VCM project is receiving a lot of attention in the company, particularly from a safety perspective. As Mr. Star knows, the VCM plant has been the subject of numerous HE studies, which identified several ways to improve the safety of the plant design. The objective of 's visit is to ensure that this well-designed plant is also built as designed. Tb accomplish this, he will meet with the people responsible for installing each major equipment item and ask them a number of questions from his checklist. He also plans to visually inspect each major piece of equipment and, in fact, prefers to review his checklist with the personnel at the equipment site. Following this discussion, takes a tour of the site. During this tour he takes note of any unsafe practices he observes and immediately brings them to the attention of the appropriate personnel. is now ready to begin his Checklist Analysis. The first item to examine is the HC1 storage tank (shown in Figure 16.1, on the following page). Participating in the review are (the contractor's engineer for the tank farm) and (the contractor's inspector). Using his storage tank checklist as a guide, begins the review. Tb start with, has an NDE (nondestructive examination) of the HC1 tank been performed? Yes, two weeks ago. How was this done? The NDE was performed by Leakiest, Inc. They have done most of the NDE work for us on th* site. For

4 TOP PLAN SOUTH Л FVAT1DM EAST ELEVATION MARK В D NOZZLE SCHEDULE SIZE TYPE DESCRIPTION 150 FILL 20" MANWAY MANWAY ISOf! DISCHARGE VENT DESIGN DATA DIMEN: 8' OIA. X 16* STR. SIDE CAPAOTY: GAL DCS, PRESSURE SHELL: 50 PSIG OPERATING PRESSURE SHELL: ATMOS DESIGN TEMPERATURE SHELL: 250T ОРЕЯАЛМС TEMPERATURE SHELL 120T TEST PRESSURE SHELL: 100 PSIG SHELL THICKNESS 5/16" MATERIAL OF CON STR. CARBON STEEL REMARKS: FIBERGLASS LINED DRAWING NO. H-107 SCALE: NONE на STORAGE TANK ABC VCM PLANT ANYWHERE. USA DRAWN BY DATE DFM 9/8/88 CHECKED BY DATE WG8 10/20/88 REV DATE DESCRIPTION I I Figure 16.1 Schematic of the HC1 storage tank.

5 this tank, my records show that they radiographed all the welds. I personally checked the radiographs and also visually inspected the welds. Are the Leaktest examiners certified by ASME? And is the NDE method they used ASME-approved? Yes and yes. We checked their certification before hiring them. Do you have the results of the NDE? Sure, they're with the engineering files for the HC1 tank. Would you like me to get them from the trailer? Later. Let's move on. Did you heat treat the welds? Yes, according to code. And we performed Brinell hardness testing on samples of the steel used to construct the tank. And the results are on file? Same file as the NDE results. I'll get that later also. Okay., did you check the foundation installation and tank support anchors? Yes, we did that both before and after tank installation. What about the materials of construction? Did the tank material, welding material, and gaskets comply with the equipment specs? Yes, as you can see, the equipment list and construction drawing specifies a fiberglass-lined, carbon steel tank. Note the nameplate on the tank \points to nameplate]; it's carbon steel. By the way, it looks like the ground inside the diked area slopes towards the tank. Shouldn't it be the other way? You're right. I'll make a note to correct this. I don't have the grading drawings with me. How large is the dike supposed to be? One-and-a-half tank volumes. Okay, hang on a minute. [ walks off the dimensions of the dike and then estimates its volume. Satisfied that it is about right, he moves on to other items.] Let's see, you already said all the welds were tested and inspected. How about tack welds on vertical joints? Were they removed?

6 We chipped them all off and smoothed the surface. I think checked this also. [ nods yes.] Okay, I see the tank plate looks fine and accurate. Did you do a hydrotest? Yes, that was done and I have the test results on file. Did you see any settling due to the hydrotest? No. We checked the tank foundation elevation after the hydrotest and it was within specs. Have you checked the physical dimensions of the tank? Proper height, diameter, and roundness? Yes, that was all done. How about the elevation and orientation of the nozzles? Is the tank plumb and on centerline? Yes. In fact, I did that myself. I see you've got your tape measure there. Let's do a rough check on the distance between the top and bottom nozzles. [McNamara measures the distance and it comes out okay.] Looks like the grouting is okay. Are the foundation bolts tightened? Yes. They should be torqued as recommended on the construction drawing. Sounds about right. Think that pipefitter over there \points to left] will loan us his torque wrench? Not a chance. But he'll check it out for us. Hey Joe, can you check the torque on a bolt for me real quick? [Joe comes over and verifies that the foundation bolts are properly torqued.] Let's see now. Item 11 on my list is ladders and platforms. They look right. Item 12, trays level and correct orientation. That doesn't apply. Internal pipes installed with correct bolts and gaskets? [McNamara nods yes.] Let's go up top and look in the manway. Okay, but there's only one ladder. Only one person at a time should be on the ladder. [ climbs to the top and looks in the manway.] From what I can see, the dip leg looks okay. Hey McNamara, isn't this tank supposed to be lined? Sure, it's an HC1 storage tank. I think you'd better take a look. [ exchanges places with ]

7 Holy Moly! They forgot the #*?x$! lining! That's a major item. I'll have to go back now and check our paperwork to see what happened. I agree. However, IVe only got a few more items. Let's go ahead with these items and finish the tank. What kind of gaskets are on the tank? The equipment specs say paper, and that's what we have. This is an atmospheric tank. Internal tray manways closed. That doesn't apply. Packing installed doesn't apply. Is this tank to be insulated? Not according to the specs. Let's verify the instrument taps and atmospheric vent and I'll be done. [The team visually checks all the storage tank taps and the vent.] Upon completing his review of the HC1 storage tank, moves on to the HC1 transfer pump, which is in the same area. Using a checklist for pumps, he begins the review process over again. This examination of equipment continues throughout the week, with and appropriate teams of construction inspection personnel. During times when he is not in the field, verifies some of the QA paperwork for equipment items that had an unusual number of deficiencies during the Checklist Analysis. At the end of each day he documents the deficiencies found for Mr. Star's follow-up. 163 Discussion of Results For the most part, documents the Checklist Analysis and Safety Review results by initialing his checklist form as he performs the review (Tkble 16.1 is an example of a partially completed checklist). Checklist items requiring further attention are noted on his form and described in a separate table attached to the checklist (Tkble 16.2). Important findings from the Checklist Analysis were (1) the tank lining was missing and (2) the ground inside the diked area needed to be sloped away from the tank. In addition, made several observations during his visual audit of the construction site. These include the following: Some hot work areas were not free of flammable materials. Heavy equipment work using cranes was not always adequately monitored. Completed, inspected work was not always properly tagged (leaving it vulnerable to further, perhaps uninspected alterations). provides his checklist results to Mr. Star at the conclusion of the site visit.

8 Tkble 16.1 Checklist Analysis Results for the Hd Storage Tknk Inspection Item Tb Check 1. Nondestructive examination (NDE) performed a. NDE examiners are ASME-certified b. Approved ASME NDE method used c. NDE results in engineering file 2. Postweld heat treatment and hardness testing performed a. Postweld heat treatment in accordance with ASME code b. Brinell hardness testing performed c. Test results in engineering files 3. Vessel foundation elevation and slope checked 4. Vessel material and construction materials in compliance with specifications and job requirements 5. All welds inspected and tested 6. All tack welds in vertical joints properly removed 7. Vessel wall plate in good condition (or properly repaired if damaged) and contains all pertinent information 8. Vessel hydrotested 9. Dimensional check of vessel performed 10. Elevation and orientation of nozzles checked. Vessel is on centerlines, is level, and is properly grouted. Foundation bolts tightened 11. Ladders and platforms installed as per drawings 12. Hays level and correct orientation. Downcomer clearance, weir height, drain holes, gaskets, bolts, etc., installed per specification 13. Internal pipes installed with correct bolts and gaskets 14. Internal lining intact 15. Internal tray manways closed 16. Packing installed O.K. (Sign and Date) Action Required Not Applicable Action Required Not Applicable Not Applicable Tkble 16.2 Action Items from the Hd Storage Tbnk Checklist Analysis No. Action Responsibility Date 3 Verify HC1 storage tank basin is graded away from the tank 14 Verify lining is installed in HC1 storage tank

9 16.4 Follow-Up The Checklist Analysis/Safety Review was used to audit the construction of the VCM plant and the deficiencies identified were addressed. Usually, the appropriate contractor personnel were present whenever the Checklist Analysis uncovered a deficiency, and they initiated actions to correct the problem. Tb ensure this, Mr. Star assigned ABC personnel at the site the responsibility of verifying that every problem identified by was corrected. Mr. Star tracked the corrective actions weekly, meeting with appropriate personnel to determine the status of these corrections Conclusions and Observations The Checklist Analysis/Safety Review proved quite successful in uncovering construction deficiencies, primarily because had good checklists and extensive plant construction experience. In addition, the review was successful because personally checked the equipment to ensure it met specifications rather than relying solely on the experience of plant personnel. Several other important observations can be made about the Checklist Analysis: The Checklist Analysis can be used both as an investigative tool to identify hazards and an audit tool to verify designs and installations. In this example, the design had been thoroughly reviewed with other HE methods, thus the checklist was used primarily as an audit. The Checklist Analysis/Safety Review is not all-inclusive and should prompt additional questions from the reviewer. did not limit himself to the checklist or the Safety Review, but asked additional questions as he thought of them. 's verification of the responses to checklist questions varied. As he gained confidence in the team's answers (by checking some of the records on the equipment item), he did less physical checking of the equipment. An experienced person is needed to perform a Checklist Analysis, especially if the review is being done as an audit. For the amount of equipment examined, the Checklist Analysis/Safety Review went very quickly. Table 16.3 summarizes the time required to perform this review. Tkble 163 Checklist Analysis and Safety Review Staff Requirements for the Construction/Start-up Phase Personnel Preparation (hr) Evaluation (hr) Documentation (hr) Leader* Team Member* 0.5 * Average per equipment item.