As more fleets contemplate using natural gas to fuel their vehicles, questions also arise as to how such a switch might impact maintenance practices.
For example, JX Enterprises, a chain of 15 medium- and heavy-duty truck dealerships headquartered in Waukesha, WI, spent north of $30,000 to make several of its truck service bays ready for natural gas. When it built its 28,000-sq.-ft. JX Truck Center facility in Kronenwetter, WI, last year, the company beefed up a “firewall” between its maintenance and body shop bays, as well as an in-floor heating system powered by waste oil to remove open flame issues.
“We’d just finalized the plans when we started talking about the growing demand for LNG (liquid natural gas) and CNG (compressed natural gas). That’s when we revisited the plans with our contractor to see what we needed to do in order to work on such equipment,” says Sam Stevenson, general manager of the facility.
Thus, one of the challenges fleets face when exploring a changeover to natural gas power is finding information concerning what shop upgrades need to be done in order to comply with fire and safety regulations where this gaseous substance is concerned.
Helping fleets deal with the challenges of making the switch to natural gas is a key service of organizations such as Clean Fuels Ohio, explains Jerrold Hutton, the group’s director of its gaseous fuel transportation partnership. The company offers guidance on how to update maintenance facilities and practices to safely work on natural gas-powered equipment.
“For example, if you’re going to put a [natural gas vehicle] in the shop for a while, you’ll need to ‘de-fuel’ the unit,” he says. “But you can’t just release the fuel into the air. You need to offload it by attaching it to a compressor station to remove the fuel from the vehicle and put it back into storage.” It’s also important to note that odorants are added to both LNG and CNG so drivers and shop technicians can identify if a leak has occurred; however, both act slightly differently when expelled into the atmosphere.
“Natural gas is lighter than air and has a limited range for combustion; between a 5% and 15% concentration in the air is when it can ignite,” Hutton explains. “Yet LNG is stored at -240 deg. F so it liquefies; once it reaches -30 F, it then reverts to a gas and behaves like CNG.”
But because it is stored at such cold temperatures, LNG will produce a visible “vapor cloud” if released. Hutton notes, too, that if a driver or maintenance technician notices a sheen of ice forming on the fuel tanks of an LNG truck, that’s an immediate sign that there is a leak between the inner and outer wall of the tank.
Fleets also need to pay close attention to National Fire Protection Assn. (NFPA) codes regarding facility safety in relation to gaseous substances—in particular sections 52, 58 (for propane), 59 A (for LNG), 30 and 30 A (for flammability and combustibility rules), 70 (for national electrical codes), and 88 A (for structural rules).
Hutton explains, though, that the NFPA codes serve only as “guidelines”; local authorities retain the final word on shop compliance. “They determine all the fire protection considerations for your facility,” he says. “The main issue they focus on is the potential accumulation of flammable gases, so they will evaluate ventilation needs, how much air needs to be moved per square foot per hour, etc.”
Overhead heating systems, for example, are often a no-no in shops working on natural gas vehicles as are infrared heaters. The scope of paint booth activity is limited by the proximity of natural gas equipment.
Hutton says the best advice his group offers to fleets is to isolate a single bay within the maintenance facility so it can be dedicated to handling natural gas-powered equipment. “That really offers a lower cost solution versus spending six figures to upgrade the entire shop,” he notes.