basic piping

[glazetm]

can anyone tell me when a branch outlet becomes a saddle. We have a pipe we are stubbing into another pipe and making a full pentration weld. At which size will this pipe be concered a saddle. Is it 1/2 of the dia. of the pipe being stubbed into.

Thanks,
Tommy

 

[pennpiper]

Your question is addressed in the Piping Codes.
Piping Codes:

Piping codes define the requirements of design, fabrication, use of materials, tests and inspection of pipes and piping systems. A code has a limited jurisdiction defined by the code.

B31.1 - Power Piping
This code contains requirements for piping systems typically found in electric power generating stations, industrial institutional plants, geothermal heating systems, and heating and cooling systems.

B31.3 - Process Piping
This Code contains requirements for piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, & cryogenic plants, & related processing plant terminals

B31.4 - Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids
This Code contains requirements for piping transporting crude oil, natural gas liquids, liquefied petroleum products and other liquids between natural gas plants, refineries, and other facilities.

B31.5 - Refrigeration Piping and Heat Transfer Components
This Code covers materials, design, fabrication, assembly, erection, test and inspection of refrigerant, heat transfer components & secondary coolant piping for temperatures as low as -320°F (-196°C).

B31.8 - Gas Transmission and Distribution Piping Systems
This Code covers the design, fabrication, installation, inspection, testing, and safety aspects of operation and maintenance of pipeline facilities used for the transportation of gas.

I recommend you get a copy of the proper "Code", read it and act accordinly.

prognosis: Lead or Lag

 

[MJCronin]

Tommy,

A branch element does not "become" a saddle at any one point.

This is equivalent to asking a structural steel designer "When does a W8 become a W12 ?"......the answer is, of course, it depends....

The piping designer is responsible to insure that piping intersections (tees and branches) meet the pressure reinforcement requirements of the appropriate code. ASME B31.1 and B31.3 have very specific and well defined rules about this.

The reinforcement requirements FOR A SPECIFIC PIPING SYSTEM are contained in a table in the piping line spec. This specification is developed by an engineering firm.

What is suitable for one piping application (based on pressure, material selection and operating temperature) may not be suitable for another !

There are components, such as weldolets, that can take away much of the guesswork.

Hope that this helps....