Section 408.4246. Blowoff connections; existing power boilers.

(1) The construction of the setting around each blowoff pipe shall permit free expansion and contraction. Careful  attention   shall   be given to the problem of sealing these setting openings without restricting the movement of the blowoff piping.

(2)   All blowoff piping, when exposed to furnace heat, shall be protected by firebrick or other heat-resisting material, so constructed that the piping may be inspected readily.

(3)    Each boiler shall have a blowoff pipe, fitted with a valve or cock, in direct connection with the lowest water space. Cocks shall be of the gland or guard type and suitable for the  pressure  allowed.  The  use   of globe valves shall not be permitted.

(4)   When the allowable working pressure exceeds 100 psi  gauge,  each blowoff pipe shall be provided with 2 valves or a  valve   and  cock,   such valves and cocks to be at least of the extra-heavy type.

(5)    When the maximum allowable working pressure exceeds 100 psi gauge, blowoff piping shall be at least extra-heavy and shall be run full size without use of reducers or bushings. The  piping  shall   be  at  least extra-heavy wrought iron or steel and shall not be galvanized.

(6)   All fittings between the boiler and blowoff valve shall be of steel.

In case of renewal of blowoff pipe or fittings, they shall  be  installed  in accordance with the rules and regulations for new installations.

(7)   Each steam heating boiler  shall   have  a  blowoff   pipe   connection fitted with a valve or cock not less than 3/4 inches pipe size connected with the lowest water space practicable.

History: 1979 AC.