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Navigating A Natural Gas Shop Conversion
If you’re planning to add natural gas trucks to your fleet, you will likely have to make some modifications to your shop. That exercise could go smoothly or not, depending on how much homework you do in advance.

Monarch Beverage in Indianapolis retrofitted its large shop with gas-safe light fixtures, methane detectors and ventilation fans as part of a conversion to CNG-powered tractors. Photo: Tom Berg

Monarch Beverage in Indianapolis retrofitted its large shop with gas-safe light fixtures, methane detectors and ventilation fans as part of a conversion to CNG-powered tractors. Photo: Tom Berg
If you’re planning to add natural gas trucks to your fleet, you will likely have to make some modifications to your shop. That exercise could go smoothly or not, depending on how much homework you do in advance.
Speaking at the Green Fleet Expo and Conference in Schaumburg, Illinois, in October, Mark Ellis, central region manager for the Maintenance Design Group, offered up 20 years worth of experience in designing and building such a facility. He said with all the conflicting code and standards across the country, it’s best to choose designers and contractors that know the local market — and to start the conversation early with local regulators and enforcement officials.
“The scariest part of a shop conversion is the codes and what the agencies that have jurisdiction over your shop will enforce and make you do as you begin incorporating alternative-fueled vehicles into your fleet,” he said. “You’re dealing in some cases with state, county and municipal governments, and no two across the country seem to be on the same page on this.”
He said 43 states have adopted the National Fire Protection Association and the International Building, Fire and Mechanical codes. However, only 13 states have controlling enforcement over all other state agencies. In many cases, local code officials have local code adoption capability. City councils in some areas can adopt codes, as might the city planning departments. Fire marshals, too, can adopt codes.
There are even conflicting codes in some cases.

A buildup of gas will trigger alarms, activate fans and open doors. The system is wired to the local fire house so firefighters can automatically be called. Photo: Tom Berg
“You can look at the NFPA books and see conflicts between the 2009 and the 2012 versions,” he notes. “Beware of what version you’re working from.”
Code compliance is only one piece of the puzzle. The kind of shop you plan to build can make a difference, too. Many jurisdictions make distinctions for so-called minor-repair garages versus a full-service shop that does engine overhauls, for example.
“Some of the newest codes exempt minor repair garages, or apply less stringent standards related to ventilation and electrical,” Ellis said. “With that said, there are still codes and standards that apply to minor repair garages.”
Ellis advised fleets to begin the process with an open mind, and be ready to consider modifications to their plans, such as functional separation where you split the work into two or more location based on task. That might keep the major work in one facility, or on one side of the shop, and the minor work in another.
In major repair facilities, there are requirements for ventilation and air turnover that are quite demanding and can be very expensive to operate. Methane detections systems can in some cases be used with less demanding air exchange requirements, but these requirements vary. Again, it pays to get talking with your contractors and city officials before getting too deep into the planning process. It’s really helpful when the contractor has a good working relationship with the code officials as well as enforcement officials.
Based on previous experience, Ellis offered these three tips on getting the project off to a smooth start and bringing it to a successful conclusion.
1. Control the risk assessment narrative: There are many misconceptions about natural gas, so set the tone of the discussion with research-based facts, and be up front about what you plan to do and what will be going on in the shop.
2. Keep lines of communication open: Get everyone involved in the project talking early and keep them talking all the way through the process. Don’t let the misconceptions about natural gas torpedo your project at the last minute.
3. Look for opportunities to compromise: There can be trade-offs between ventilation requirements and, say, ceiling design, methane detection systems, and electrical modifications. Explore all the possibilities.
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