Section 041-15-4 - Power Boiler Repair or Replacement by Mechanical AttachmentA. The mechanical attachment of piping and components within the code boundary on power boilers associated with the major boiler systems must be completed by R Certificate Holders. Major boiler systems consist of the main steam system or equivalent, the feedwater system, the blow-down system, and any repairs or replacements associated with tubes. (1) The owner shall submit documentation on each repair/replacement on the Mechanical Repair Form approved by the Board.(2) The documentation shall include material traceability and verification of the construction standard.(3) A hydrostatic test to verify mechanical integrity shall be conducted upon completion of the repair/replacement.(a) The minimum permissible metal temperature during the hydrostatic test shall be as required by the code of construction but in no case less than 60 degrees Fahrenheit.(b) The test pressure shall be at least 80 percent of maximum allowable working pressure of the object.(4) The jurisdictional Inspector must document all mechanical repairs on a form provided by the Board.B. The mechanical attachment of piping and components within the code boundary on power boilers not associated with the major boiler systems may be performed by individuals under the supervision of the engineer-in-charge. (1) The owner shall submit documentation on each repair/replacement on the Mechanical Repair Form provided by the Board.(2) The documentation shall include material traceability and verification of the construction standard.(3) A hydrostatic test to verify mechanical integrity shall be conducted upon completion of the repair/replacement.(a) The minimum permissible metal temperature during the hydrostatic test shall be as required by the code of construction but in no case less than 60 degrees Fahrenheit.(b) The test pressure shall be at least 80 percent of maximum allowable working pressure of the object.(4) The jurisdictional Inspector must document all mechanical repairs on a form provided by the Board. Note:
Notes are provided for informational or explanatory purposes. They are intended to provide guidance and/or to clarify the rules. They are not part of the rules.
Repairs in this chapter refer to restoration or replacement of pressure retaining items and do not include other maintenance activities associated with the operation of the boiler.
The NBIC defines repair as the work necessary to restore pressure retaining items to a safe and satisfactory operating condition. Additionally, it defines pressure retaining items as any boiler, pressure vessel, piping, or material used for the containment of pressure, either internal or external. The pressure may be obtained from an external source or by the application of heat from a direct source, or any combination thereof.
1. Repairs, as used in this chapter, are limited to the code boundary for the object or system. For example, on high pressure boilers repairs to boiler external piping would be included. The boiler external piping includes all the piping and appurtenances out to and including the required valves. The specific boundary may vary based on the number of boiler(s) connected in a battery. However, in general it includes:
A. The feedwater piping and valves out to the second valve;B. The blowoff piping out to and including the second valve;C. The main steam piping out to and including the first valve on a single boiler installation;D. The main steam piping out to and including the second valve on a multiple boiler installations; andE. Piping for gauges, controls, low water fuel cutoff etc. out to the first valve. The boundaries are detailed and specified in Section 1 and B31.1.
2. On low pressure boiler the code boundary ends at the boiler proper which is at: A. The first circumferential joint for welding end connections;B. The face of the first flange in bolted flanged connections; orC. The first threaded joint in that type of connection.3. On pressure vessels the code boundary ends at the pressure vessel proper which is at:A. The first circumferential joint for welding end connections;B. The face of the first flange in bolted flanged connections; orC. The first threaded joint in that type of connection.4. The following is a list of examples of typical repairs. It is not meant to be all inclusive but is provided for the purpose of illustration. A. Replacement or repair of piping and fittings associated with boiler external piping. This includes piping for appurtenances;B. Welded repairs to the pressure vessel, boiler or piping;E. Replacement of handhole or manway covers;F. Replacement of valves;H. Attachment welds to pressure part.02-041 C.M.R. ch. 15, § 4