How to engineer manufacturing, industrial buildings
CSE: What buildings have you retrofitted to become a new manufacturing plant? Share stories of microbreweries or other unique retrofits.
Larson: Our manufacturing work involves reconfiguring existing assembly lines and building new manufacturing spaces or expansions using adjacent existing space. Knowing what’s there and what can’t be interrupted is key to successfully implementing changes and additions. Taking the time to get as familiar with the site as possible is critical, along with understanding the risks of moving forward with unknown conditions that are either too difficult or too expensive to verify.
CSE: What are some challenges you have faced in coordinating structural systems with mechanical, electrical, plumbing, or fire protection systems?
Schlagetter: The pace of projects sometimes requires work to be performed out of sequence, with less decisive information, requiring more field coordination in smaller footprints and building volumes. Ingenuity and field engineering often rule the day, with only the end points and rules for routing defined.
Regan: On a recent overseas project we were given conceptuals by the owner’s designer (not an architect) of how he wanted his new facility to look. The interior space had large unsupported walkways and clean, sharp lines. The problem was that there was no space for relatively large conduit runs, chilled water, HVAC ducts, sprinklers, plumbing, etc. The owner’s face dropped when we gave him this news. His dream seemed dashed! Our engineers said, “Give us a day or two to work up some sketches.” They delivered conceptuals that gave him the look he wanted. Interior corridors and galleys were added for the infrastructure needs. While he lost rental square footage in this design, he was more than happy to get the look he wanted and sacrifice the rental space.
Sims: A major challenge on some of my recent projects was coordinating very early smoke detection apparatus (VESDA) sampling pipes and cable trays with structural and mechanical systems. The biggest hurdle involved the level of detail in the design model in comparison to the construction model. We were contracted to produce routing of the structural and mechanical systems but not the supports. The construction model was contracted to produce a much higher level of detail including pipe supports. This created a lot of rework when the construction model was integrated into the design model. This highlights the importance of one model for construction and design with similar levels of detail.
Larson: Change occurs throughout the design phase of nearly all manufacturing plants. There are always new products, ideas, and tools that become available to our teams as design develops. New coordination tools such as Revit are helping to manage change, but the key is to maintain flexibility in the overall production process so that change (which really is inevitable) does not impact the design delivery schedule. In manufacturing, delays are costly, and the ability to manage change without sacrificing schedule is key to being able to keep your clients happy.
CSE: Many such facilities, because of the nature of the chemicals and equipment they work with, have special hazmat considerations. How does that come into play in your work on such projects?
Schlagetter: We have to be prepared to ask questions about requirements not in our scopes of work, to help ensure the customer has considered them. For example, U.S. EPA requirements for containment buildings when we are only specifying a prefabricated storage unit, or the provision of tepid water or a safety shower when we are not responsible for the plumbing scope of work.
Larson: Hazards come in many forms. For mechanical, electrical, plumbing (MEP), and fire protection engineers, these hazards usually arise from high pressure and high voltage. Many of these hazards can be mitigated by having the right construction team in place. These teams need to be qualified, have recent relevant experience, and know what is really at stake if they try to take shortcuts. Everything is schedule driven, and sometimes the need to make schedule can take a higher priority than doing things the right way. A very tight specification that qualifies the individual installers coupled with a rigorous thorough inspection process is key to making sure hazards are mitigated. If you don’t know that you can trust the installer, find another one that you can.
Sims: My department is responsible for the hazardous production monitoring system. This encompasses toxic and flammable gas detection. We use a redundant programmable logic controller (PLC) system to interface with the detection equipment and send control signals to the gas delivery equipment. There is also a liquid leak detection system that interfaces with the PLC to monitor for process chemicals that may pose a risk to the safety of the employees and the facility. We also install a VESDA system and/or flame detection in flammable chemical areas. Access to these areas is limited by an electronic access control system with closed-circuit TV. This is becoming a prescriptive requirement due to the Dept. of Homeland Security involvement in inspecting high-hazard buildings (H occupancy).
Regan: A good portion of our firm’s business revolves around the petrochemical industry. New federal and state regulations require more specific documentation on the hazardous areas and the installation of the electrical systems that are located in these areas. Our petrochemical engineers are well-versed in electrical area classification issues for hazardous gases and liquids. More often than not, we need to take extreme and costly measures to meet the regulations. For instance, substations in hazardous areas must be dual pressurized from clean air sources to keep explosive gases from entering the substation to ensure safety. Sometimes that means clean air stacks rise 40 to 50 ft to find clean air sources. When you have 120 major pressurized substations in one refinery, the instrumentation and controls become a major concern to ensure safety. Fitting new substations into such hazardous areas may require raising them to extreme levels to compensate for possible release of high volumes of heavier-than-air explosive gases. Compound that with post-Hurricane Sandy requirements to raise substations yet supply explosion-proof seals in such to meet NFPA requirements, and another set of challenges arises.