From a Whistle to a Hum: Facilities Upgrades Enhance the Resilience of the Campus Steam Distribution System
Editor’s Note: This article is a follow-up to an earlier piece published in the MIT Faculty Newsletter, January/February 2009.
Hypothetical conversation overheard between two students at the Lobby 7 coffee shop during Fall Term:
Elizabeth: “Hey Alex. Where are you headed?”
Alex: “Oh, hey Elizabeth. I’m on my way to Building 66 for 10.302.”
Elizabeth: “Oh, you’re Course 10? I thought you were 7?”
Alex: “No, Course 10 but I’m thinking of doing both 10 and 7 since I’m pre-med anyway. Depends on if I can manage 60 units a term for the next 4 terms. Did you decide to stick with 16?”
Elizabeth: “Yeah. Unified was pretty tough – it felt like 100 units of work for 48 units of credit. But I got through it ok and I think it’s helping me understand 16.07 this term. Speaking of ok, how is Building 66? Didn’t some big flood or something happen there a year or two ago?”
Alex: “There was a steam line rupture on Halloween night and some of the sprinklers activated, so that’s how the flooding happened. Sub-basement had to be redone. I remember UROPing in 66 that IAP. Second floor lounge was closed and there were a bunch of contractors around. But almost everyone seemed to be able to keep working in the labs from what I could tell. People in 10.26 and 10.29 had to do lab somewhere else that spring, and there was some scrambling to finish out 10.28 since the lab space was closed and the fall term was more than half over. Other than that it sounds like we got lucky. No one was hurt and I don’t think any of the grad students lost their work.”
Elizabeth: “Sure, but don’t you wonder if something like that could happen again? Or even somewhere else in the Institute? Look at all those steam lines along the tunnels in the Infinite Corridor and 18 and E25. Was the actual problem fixed?”
Alex: “Well, it seemed like there was a lot of effort to fix things and I heard Facilities worked through that weekend to make sure people would be able to get back in the building. I’d be surprised if MIT risked that kind of thing happening again. From what I’ve been told, it was a close call. But for now, my worry is staying awake through recitation and making it through the rest of this week. I have an exam on Friday, a fencing tournament Saturday, and am going on 3-1/2 hours of sleep from finishing a lab report.”
Elizabeth: “No kidding. I have a 24.00 paper due Friday on top of my 16.07 exam. If I’m lucky I’ll be able to recharge before my house’s fall semi-formal on Saturday. Good luck on Friday.”
Alex: “Good luck to you too. See ya.”
While you’ll have to look to the end of this article for the answer key, in the meantime let’s explore how these numbers are related to one another and to the hypothetical conversation above.
Our friends Elizabeth and Alex are two of among approximately 21,000 individuals who can be found in various corners of the Institute, going about their daily lives at MIT – in lecture halls, in meeting rooms, in recreational facilities, in academic offices dotted throughout more than four dozen buildings, and in administrative offices and living groups spanning all four corners of the MIT campus. For most of us, our typical daily routine may involve visiting a handful of buildings – possibly six or even 10 out of the more than 150 buildings that comprise the entire MIT Cambridge campus. If you are a member of the Repair and Maintenance staff in the Department of Facilities, however, chances are you have walked through nearly each and every one of these 150 buildings, sometimes covering more than a dozen buildings in one day. That equates to approximately 12.1 million square feet of building space, powered by electricity and whose heating, ventilation, and air conditioning systems run on steam that circulates through approximately 16,000 linear feet of distribution line. If one considers the 12.1 million square feet of building space as a skeleton that frames the physical body of MIT, then the three miles of steam piping, together with miles of water/wastewater distribution lines, and telecommunication and electrical cable form a circulation system for critical campus infrastructure. The various sensors and alarms are its nervous system, signaling when the system is functioning at steady state and when there is cause for concern.
Two years ago at 8:30pm on Friday, October 31, 2008, the condensation-induced water hammer that occurred in 200 psi, high-pressure steam piping in the Building 66 sub-basement mechanical room generated enough force to cause catastrophic failure of pipe anchors secured to the concrete ceiling slab.
These pipe anchors supported the steam distribution line, which included an expansion joint designed to allow the system to handle movement due to temperature changes. With the pipe anchors uprooted, the energy contained in the pipe was of enough intensity to transfer movement from the pipe to the expansion joint, pulling it apart and creating a release point for the steam. When the Department of Facilities staff inspected the line on Saturday morning, they discovered that a steam trap – a simple mechanical device designed to collect condensation and thereby prevent the temperature differential that can lead to water hammer – had failed. While Facilities staff worked ceaselessly over more than 24 hours to return the building to normal operation by Monday morning and the Environmental Health and Safety Office surveyed the building for re-occupancy, it was clear to Facilities leadership that an incident investigation and renovation of damaged spaces in various areas of Building 66 would not be enough. On the contrary, specific risk prevention measures would be necessary to ensure the events of October 31, 2008 would be lessons learned and not chronic recurrence.
One of the overarching lessons learned was that any risk prevention measures needed to be systematic in nature: Not only did the measures need to consider all of the contributing causes to the incident in Building 66 specifically, they also needed to consider the entire campus distribution system. Engineering improvements to the steam distribution system in Building 66 would only be as resilient as its weakest point. Ultimately, corrective and preventive actions followed a three-pronged strategy of Review, Repair, and Re-engineer.
The Department of Facilities retained a consultant to undertake a review of the entire distribution system. The scope of work focused on the high pressure and medium pressure steam system in buildings, with the specific deliverable to locate all steam traps and expansion joints and report on their function and condition. Additionally, the Department of Facilities also undertook an inspection of the structural systems that attach the steam system to the building, and the results were compiled in a report that also included a prioritized list of deficiencies for mitigation. The ranking scheme assigned highest priority to evaluating expansion joints, a now recognized failure point in the distribution system, in those locations with the potential to expose people in the event of a catastrophic malfunction.
In recognition of the root cause of the incident, i.e., the failed steam trap, the Department of Facilities Repair and Maintenance (R&M) group expanded its preventive maintenance program to include all steam traps and expansion joints. In the preventive maintenance program, work requests are automatically generated on a recurring schedule that is pre-set by the individual in charge of that operation; thus, the Department of Facilities work order request system will automatically and periodically generate a work request for an R&M tradesperson to inspect and perform maintenance. The effort effectively represents a “no steam trap or expansion joint left behind” approach to removing this potential route for a steam line failure.
Further recognizing the potential risk posed to a Repair and Maintenance tradesperson who is commissioned to inspect and repair steam traps, the Department of Facilities engaged faculty expertise to learn whether and how we could make conditions safer should a repair person attend to a situation like the one present in Building 66 just before the steam release.
A critical lesson learned from the October 31, 2008 steam incident is that expansion joints can catastrophically fail. In the ensuing incident investigation and corrective action review, original engineering design assumptions were questioned and tested. One conclusion resulting from this analysis was that since the local steam distribution system would require repair, this might be a prime opportunity to re-engineer the steam system in the sub-basement of Building 66 to eliminate the need for an expansion joint. As a follow-up to this steam distribution re-engineering project, the Department of Facilities now has underway the removal of the expansion joints in the tunnel between Buildings 16 and 54 and in Building 16 proper. Engineering design of the expansion loop, which will replace the joints, is completed. The Building 16 and Building 54 locations were determined to be of highest priority and the intent is to progress to other buildings throughout campus that are also served by high and medium pressure steam piping.
Finally, Repair and Maintenance has underway a pilot program to test the value of monitoring all high-pressure steam traps in Buildings 66, 68, 56, and 54. The software uses remote sensors at each trap to assess its effectiveness and report, on an hourly basis, its status to the supervisor responsible for these steam systems. This information enables the appropriate staff to evaluate the potential for incident precursors and to intervene before a problem manifests.
In aggregate, these individual projects will help ensure that the campus steam distribution system, and the infrastructure it supports, is more resilient and does not succumb to circumstances that may be foreseeable and preventable. The Department of Facilities motto is “Making MIT Work.” The January/February 2009 edition of this newsletter chronicled the events of October 31, 2008 as “When a Whistle in the Wind is the Sound of Steam: Lessons Learned from a Building Emergency.” In November 2010, the Department of Facilities is proud to announce our progress in transforming the whistle to a hum, the hum of systems that operate – resiliently – at steady state and allow our campus community members like Elizabeth and Alex to worry about exams, papers, semi-formals, fencing, etc. and not about the overall safety of the buildings through which they walk and in which they work.
Answers: a-j; b-l; c-h; d-i; e-g; f-k