Iowa Admin. Code r. 875-91.8 - [Effective until 3/26/2025] Plugging boiler tubes
This rule does not apply to tubes in headers of economizers, evaporators, superheaters, or reheaters.
(1)
General requirements.
a. Leaky tubes shall be replaced or
plugged.
b. Tube plugs shall be
made of a material which is compatible with the material of the boiler tube
being plugged and shall be welded into place or manufactured to be expanded
into the tube sheet or drum.
c. The
maximum number of tubes that may be plugged shall be the lesser number
specified by the OEM or an engineer experienced in boiler design.
d. Documentation of the maximum number of
tubes that may be plugged shall be kept on site, and a copy shall be supplied
to the division of labor services by either mail or email.
(2)
Fire tube boilers.
a. A tube that is adjacent to a plugged tube
shall not be plugged.
b. All
plugged boiler tubes shall be replaced prior to the next required certificate
inspection.
(3)
Water tube boilers, unfired boilers, or process steam
generators. Water wall tubes that form a separation wall between
products of combustion and the outside atmosphere or a separation of the gas
passes in a multiple gas pass boiler shall not be plugged.
Notes
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
This rule does not apply to tubes in headers of economizers, evaporators, superheaters, or reheaters.
(1) General requirements.
a. Leaky tubes shall be replaced or plugged.
b. Tube plugs shall be made of a material which is compatible with the material of the boiler tube being plugged and shall be welded into place or manufactured to be expanded into the tube sheet or drum.
c. The maximum number of tubes that may be plugged shall be the lesser number specified by the OEM or an engineer experienced in boiler design.
d. Documentation of the maximum number of tubes that may be plugged shall be kept on site, and a copy shall be supplied to the division of labor services by either mail or email.
(2) Fire tube boilers.
a. A tube that is adjacent to a plugged tube shall not be plugged.
b. All plugged boiler tubes shall be replaced prior to the next required certificate inspection.
(3) Water tube boilers, unfired boilers, or process steam generators. Water wall tubes that form a separation wall between products of combustion and the outside atmosphere or a separation of the gas passes in a multiple gas pass boiler shall not be plugged.