The following initial discussion regarding the specification for a “True Hose”. True Hose is one which is produced to meet the demands of the fire environment, not the bottom line. The hose shall be durable, and shall bear a marking that reflects the internal diameter of the waterway.
Ideally, a manufacturer will produce 2.5" True Hose without small or unadvertised increases in diameter. These significantly increase charged water weight and reduce friction loss at handline flows.
True Hose has the following specifications (material and hose engineers please comment freely, as we are layman):
- Woven Jacket Construction.
- Double Jacketed (Nylon or Polyester or a blend).
- “Filler Yarns” are to be filament type to ensure adequate strength.
- “Warp Yarns” are to be the spun / entanglement type to both resist cutting and abrasion, but allow load transfer when damaged. This construction should also ensure a large amount of the coating is thoroughly absorbed by both jackets during the protective coating process.
- EPDM rubber liner, minimum wall thickness of .040-inches with a preference towards vulcanized rubber adhesion of the liner and jacket.
- A minimum pick count of 9.5 picks per inch (increased strength and abrasion resistance). Denier and Thickness of filaments TBD.
- Withstand Abrasion Test defined in FM Class Number 2111 to 20,000 Cycles minimum with a goal of 30,000 Cycles.
- The outer jacket shall allow less than 1/16th of an inch expansion under pressure below 200psi. Hose shall maintain its internal diameter through its service life under normal working conditions (not to exceed service test pressure).
- Goal Service Test Pressure of 400psi, but not less than 300psi.
- The inside jacket shall be manufactured using a reverse twill process to reduce friction loss.
- There shall be a durability coating of the outer jacket.
- 1 ¾” Specific:
- Total Coupled Weight goal of 17-20 pounds per fifty feet section.
- Friction loss for 50' between 19 and 20psi @ 160GPM.
- 2 ½” Specific:
- Total Coupled Weight goal of between 25-30 pounds per 50' section.
- Friction loss for 50' between 7 and 8psi @ 250GPM.
- Perform through all standard destructive tests (define this?)
- Hose shall be fully NFPA 1961 complaint and preferably (full or partial) compliance with UL 219, FM Class Number 2111 and MIL-H-24606B.
- An internal diameter that is the actual size of the marked hose size on the jacket.
- Hose length that is within 1 inch of marked length.