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(a) General Requirements.
(1) Valves, piping, and fittings shall not be subjected to working pressures exceeding those recommended by the manufacturer for the type of service for which they are used.
(2) Piping shall be so supported as to eliminate undue stresses at joints and fittings, particularly at any section of the line subject to vibration.
(3) Flexible hose and fitting assemblies and flexible couplings installed between the check valve and the cylinder on new installations or as replacements on existing elevators shall conform to the following:
(A) Installations shall be accomplished without introducing twist in the hose, and shall conform with the minimum bending radius specified in SAE 100 R2 High Pressure, Steel Wire Reinforced, Rubber Covered Hydraulic Hose. They shall be located and supported to protect hose and fittings from abrasions or undue stresses from external sources.
(B) Shall have a bursting strength sufficient to withstand not less than 10 times working pressure. They shall be tested in the factory or in the field prior to installation at a pressure of at least 5 times working pressure, and shall be marked with date and pressure of test. See Section 3009(b) for definition of working pressure.
(C) Hose shall otherwise conform to the requirements of SAE 100 R2, and shall be compatible with the fluid used therein.
(D) Hose fittings shall be of an approved type.
(E) The hose and fittings assembly shall be permanently marked with the SAE hose-type identification and the installation date.
(F) When wear, corrosion or other factors indicate that safety factor of the hose has been materially reduced below the manufacturer's rating, it shall be renewed.
(G) Flexible couplings shall be so designed and constructed that failure of the sealing element will not permit separation of the parts connected.
(b) Relief and Check Valves.
(1) Each pump or group of pumps shall be equipped with a relief valve conforming to the following requirements:
(A) The relief valve shall be located between the pump and the check valve and shall be of such a type and so installed in a by-pass connection that the valve cannot be shut off from the hydraulic system.
(B) The relief valve shall be pre-set to open at a pressure not greater than that necessary to maintain 125 percent of the working pressure.
(C) The size of the relief valve and by-pass shall be sufficient to pass the maximum rated capacity of the pump without raising the pressure more than 20 percent above that at which the valve opens. Two or more relief valves may be used to obtain the required capacity.
(D) Relief valves having exposed pressure adjustments, if used, shall have their means of adjustment sealed after being set to the correct pressure.
EXCEPTION: No relief valve is required for centrifugal pumps driven by induction motors, providing the shut-off, or maximum pressure which the pump can develop, is not greater than 135 percent of the working pressure at the pump.
(2) A check valve shall be provided and shall be so installed that it will hold the elevator car with rated load at any point when the pump stops or the maintained pressure drops below the minimum operating pressure.
(c) Supply Piping and Fittings.
(1) Supply piping materials and fittings shall conform to the requirements of Design Section 3102(g).
EXCEPTION: Flexible hydraulic hose and fitting assemblies and flexible coupling.
(2) The minimum wall thickness shall conform to the following:
(A) For working pressures up to 250 pounds per square inch, piping equal to standard schedule 40 steel pipe may be used without stress analysis.
(B) For working pressures more than 250 pounds per square inch, the wall thickness shall be not less than that determined by the formula in Section 3102(g).
(C) Pipe lighter than schedule 40 shall not be threaded, nor grooved for couplings.
NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
1. Amendment of subsection (a)(3) filed 6-23-77; effective thirtieth day thereafter (Register 77, No. 26).
2. Amendment of subsection (a)(3)(B) filed 12-22-78; effective thirtieth day thereafter (Register 79, No. 1).
3. Amendment of NOTE filed 12-8-86; effective thirtieth day thereafter (Register 86, No. 50).
4. Editorial correction of subsection (c)(2)(A) (Register 95, No. 32).
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