How to make maintenance facilities CNG compliant

What you need to know about converting a maintenance facility to CNG.

Class 1 Division 2 references an area where ignitable concentrations of flammable gases, vapors or liquids are present within the atmosphere under abnormal operating conditions. As a result, any equipment that resides in that area must be classified in order to operate under such conditions.

On the other side of that, diesel and gasoline is heavier than air and, therefore, pools on the ground and fumes/liquid seep into the floor and pits. In facilities where maintenance or storage occurs on diesel- or gasoline-powered vehicles, all equipment that falls within 18” of the floor must be Class 1 Division 2.

This is important to consider because if you are building a new facility and considering switching to CNG in the future, making your new garage CNG compliant from the start is much cheaper than retrofitting it down the road. 

In most cases, if the building being retrofitted already meets today’s codes, the cost to get it compliant with CNG codes is incremental. The problem lies in the fact that there are a lot of facilities being used regularly that do not even meet today’s standards for ventilation. These facilities cost more when being retrofitted due to the need to make them current with today’s requirements before considering CNG code compliance.



There are several different ways to become CNG compliant. There is not one correct way, or a one-size-fits-all solution.

For example, when retrofitting your garage you have the option of increasing the number of air changes, operating the ventilation system continuously or installing a bunch of methane detectors in order to detect a leak. You can also make alterations to your facility to eliminate pockets in the ceiling where gas collects, or designate a confined area where maintenance and/or storage of CNG vehicles occur to limit the amount of modifications needed.

In some cases, it may be more cost effective to build a brand new facility altogether.

If you prefer not to upgrade your facility, you can outsource the maintenance and storage of your CNG vehicles. That was the decision Try-it Distributing made when it realized that funding for facility upgrades was non-existent.

“The third part beyond the trucks and the filling station would be the building modifications to support the trucks when inside the building for maintenance,” explained Try-it’s Gicewicz. “Because we are not doing it on-site, that really took that third component off the table for us.

“I fully expected us to have to drop $500,000 to $600,000 into our facility to come up to code. It was nice that that price tag went away.”

Try-it entered into a design-build, own and operate contract with Kenworth Truck Company to service Try-it’s CNG vehicles at the OEM’s facility in Buffalo, NY. Kenworth is making the necessary upgrades to its maintenance facility there in order to service Try-it’s fleet, taking a sizable chunk of change out of Try-it’s project cost altogether. 

Try-it will still be making minor upgrades to a limited part of its facility to accommodate the CNG vehicles that are indoors briefly when being loaded with product.

The type of modifications needed depends on what the maintenance facility is being used for. For example:

  • Storage/Light Maintenance: Requires continuous ventilation or methane detection using methane detectors and then implementation of an approved response, such as increasing ventilation, shutting down electric devices and/or opening doors.
  • Heavy Maintenance: Requires continuous ventilation or methane detection using methane detectors and then implementation of an approved response, such as increasing ventilation to exceed normal ventilation rates, shutting down electric devices and/or opening doors.



Your trusted advisor can help to make sense of international, national, state and local codes and their contradictions, and navigate you through the facility retrofit. The major codes that affect maintenance facilities come from the National Fire Protection Association (NFPA). They include:

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