Laws, Rules and Regulations - The National Board of Boiler and ...

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Stamping:
Where appropriate, the following National Board stamps or ASME Code symbol stamps are required:
1. National Board: none. (“R” stamp for repair and alteration is accepted, if used.)
2. ASME Code: all.
ObJeCtS SUbJeCt tO rUleS FOr COnStrUCtIOn anD StampInG
Steam or other vapor boilers, fired pressure vessels, unfired pressure vessels for the transportation, storage, or use of any
poisonous, corrosive, or flammable substance or other products at temperatures above their boiling point at atmospheric
pressure or in which pressure is generated by means of a compressor, liquified petroleum gas and natural gas vessels, anhydrous
ammonia tanks, and air tanks, except the following:
1. Boilers and pressure vessels under federal inspection and control or exempted by the labor code.
2. Boilers on automobiles and road motor vehicles.
3. Boilers and unfired pressure vessels used in household service.
4. Air pressure tanks installed on units of transportation subject to the jurisdiction of the US Department of
Transportation, the Public Utilities Commission or the Highway Patrol.
5. Unfired pressure vessels not subject to an internal or external pressure of more than 15 psi with no limitation on size.
6. Unfired pressure vessels having an inside diameter not exceeding 6 inches with no limitation on pressure.
Such vessels must be designed and constructed according to recognized standards or to good engineering practice with a factor of
safety of at least four.
ObJeCtS SUbJeCt tO rUleS FOr FIelD InSpeCtIOn
Periodic field inspection is mandatory for the following vessels only:
1. Power boilers (both fired and unfired), except miniature boilers and small power boilers provided they are fitted with
certain automatic controls and none of the following is exceeded:
a. 100 square feet of heating surface;
b. 16-inch inside diameter steam drums;
c. 100 psi maximum allowable working pressure;
d. 35-gallon water capacity when filled to normal operating level;
e. 400,000 BTU per hour input to burners.
2. Liquified petroleum gas tanks, except cylinders made and maintained in accordance with US Department of
Transportation regulations.*
3. Air tanks, except for air tanks of 1-1/2 cubic feet or less capacity, not subject to a maximum pressure of more than
150 psi.
*With more than 125-gallon capacity including transportation tanks.
InSpeCtIOnS reQUIreD
1. Fired boilers: One annual internal and external inspection (Exception: Boilers installed in turbo-electric plants in such a
manner that each boiler furnishes steam to a single turbine – inspected internally at least once each 18 months). Title 8,
Section 770 allows fired boilers to go up to three years without internal inspection after application and acceptance by
the Pressure Vessel Unit.
2. Unfired boilers: Title 8, Section 770 allows unfired boilers to go up to six years without internal inspection after application
and acceptance by the Pressure Vessel Unit.
3. Other boilers: The division may establish internal inspection intervals other than those established for fired boilers after
application and review.
4. Pressure vessels:
a. One inspection at least every three years for portable air tanks and five years for all other air tanks. Air tanks not
exceeding 25 cubic feet in volume or 150 psi design pressure only require an initial inspection (An indefinite permit
shall remain in effect until such time as there is an alteration or change that will affect the safety of the tank.);
2013 National Board Synopsis of Boiler and Pressure Vessel Laws, Rules and Regulations