“Weighing In” on Apparatus GVW’s Keep these tips in mind when it’s time to think about weight in your fire apparatus purchase. Be careful of overbuilt apparatus. You’d never accept a bid for an underbuilt truck, but overbuilding isn’t necessarily building better. Overbuilt trucks require carriage components with heavier weight ratings, and it’s just a fact that this adds to the upfront cost of the truck. These axles, suspensions, wheels and tires contribute to a rougher ride for your crew and equipment. Overbuilt trucks use fuel less efficiently and wear components faster, adding to the longer-term costs of ownership and maintenance. A weight analysis based on real-world readiness ensures a safe truck that’s mission-ready and rides smoothly, with potential to save costs both in the build and for the service life of the truck. Include a preliminary weight analysis within the specification. Clearly state type-specific gross axle weight ratings and gross vehicle weight ratings as a baseline for weight-bearing components when writing the spec – including frame rails, axles, suspension, wheels and tires. Specifications should be written to include preliminary weight analysis parameters, clearly stating that overall weight distribution should not load weight-bearing components in excess of ratings. Make sure the specification details what the apparatus will carry to be mission-ready. NFPA lays down guidelines for establishing carrying capacity – personnel, water, equipment – but your reality may fall outside these lines based on both what your truck will and will not actually carry. Be specific about what you’ll have aboard the truck, since the combined weight of personnel, water and equipment can have a profound effect on safe acceleration, braking, and steering. Detailing the weight of mission-critical tools and NFPA-required equipment for the specified apparatus type is as important to the specification as detailing equipment lengths, widths and depths when calculating hose bed and cabinet space specifications. Require detailed weight analysis in submitted bids. When reviewing bids, be aware that different chassis, cab and body materials have unique weights. Different material specifications will figure differently toward gross vehicle and axle weight ratings, depending on the recommended configuration of the apparatus as dictated by the overall specification. Expect a cushion of no more than plus or minus 2-3% of total in weight analysis for submitted bids. Make sure gradeability and stability specifications will be met. Gross vehicle weight directly affects how braking, engine and transmission configurations contribute to these performance and safety specifications for each apparatus type. Ask about available factory tests to ensure that the truck is geared, powered and set up with a center of gravity to perform within these specifications. NFPA 1901 states that ultimately, it’s the responsibility of the purchaser to specify details of the apparatus – including those for performance and equipment that correlate to weight parameters. Do not assume a truck is buildable without in-depth weight analysis, and be sure to include weight considerations at the top of the checklist when writing specifications, reviewing bids and throughout the build and inspection process. - See more at: fire.kovatch/kme-blog/november-2014-(1)/weighing-in”-on-apparatus-gvw’s#sthash.0wQCbXEC.dpuf
Posted on: Sun, 21 Dec 2014 22:19:41 +0000