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They are designed to change the flow direction in systems or as connection tools for system parts. These fittings are also known as 150# fittings or 150 LB threaded fittings.


150 Top


1. What is Class 150# Fittings?

Class 150 fittings are commonly used in piping systems to alter directions and connections between equipment. These fittings are also used for regulating low-pressure fluid or gas. The size ranges are from 1/8” to 4” (DN6 to DN100). 

Class 150 fittings are used mainly in the plumbing, waterworks, oil, and gas industry, where there are low-pressure piping requirements. Class 150 fittings are usually used for non-critical and low-cost applications as it allows the installer to reassemble it at any time and welding isn't mandatory.

2. What are Class 150# Fittings pressure rating?

Stainless steel SS316 material ensures corrosion resistance and overall durability as compared to brass or malleable iron which have lesser corrosion resistance. Stainless steel SS316 material is applicable in all systems to last for a longer time. Class 150 fittings maximum pressure ratings are up to 150 PSI, it's usually applied and recommended in low-pressure conditions.

3. What are threaded Class 150# Fittings?

There are two types of connections available for Class 150 threaded fittings, NPT (National Pipe Thread) and BSPT (British Standard Pipe Tapered). Class 150 fitting acts as a connector, it functions to stop the leakage from the connection between two pipes.

NPT is similar to BSPT with the exception of the angle across the flanks of NPT threads being 60 degrees while BSPT threads are 55 degrees. Therefore, NPT and BSPT threads are not recommended to be used together as the connection doesn't correspond with each other. For example, NPT fitting female thread needs to tighten up with NPT male thread and the same is applicable to BSPT male and female thread.

4. What are the different types of Class 150# Fittings?

There are many fitting designs to choose from when constructing a system flow direction and flow rate calculation. These fittings are namely elbows, tees, caps, couplings, reducers, and unions, which are commonly used fittings in major systems. The majority of the fittings are female thread with exception of hex/square bush, hex nipple and street elbow, where hex/square bush and street elbow are one side male and one side female thread. Hex nipple is male threaded on both sides.

5. What are Class 150# Fittings used for?

Class 150 threaded fitting is mainly used to tighten up with fittings to extend the flow direction. Class 150 Threaded fittings are made to conform to ​ASTM A351 CF8M/316 Stainless Steel material.

6. Class 150# Fittings industry usage

Class 150 threaded end fittings are applicable in the following light duty industries to ensure continuous passage of liquid flow: 

  • Industrial cooling water systems 

  • Ships building 

  • Plumbing system 

  • Fire Protection

7. How many types of fittings are there?

Threaded fittings are available in multiple different types of fitting designs. These fittings are often customized according to the flow direction and flow rate of the hydraulic system. Below are the common threaded fittings available for use in major systems.

  • 90D Elbow – It includes both female threaded end connections which can be used to connect pipes that require a 90-degree turn of direction.

  • 90D Street Elbow – It comes with both one male and one female threaded end connection, which can be connected into 90-degree right angle bending to shift the system flow direction.

  • 45D Elbow – With both female threaded end connections, it can be installed into pipes that require a 45-degree turn of direction.

  • 45D Street Elbow - It has one female and one male threaded end connection, which can be connected to a 45-degree right angle bending to shift the system flow direction.

  • Equal Tee – T-shaped threaded fitting design which is used to connect pipes at 90 or 180-degree angles for flow transfer purposes. With three female threaded end connections, its flow is equal from the inlet port to the outlet port.

  • Reducing Tee – It can be applied at a 180-degrees or 90-degrees angle on pipes during fluid transfer. It has three female threaded end connections; however, the port sizes are 2 standard flows and 1 reducing the flow rate. 

  • Full Coupling – It has both female threaded end connections in connecting pipes for threaded fitting types.

  • Half Coupling – Design with one female threaded and one welded end connection, commonly used in welding and threaded connection alternatives.

  • Reducer – It helps to extend the pipe's connection by installing two different pipes together. Both female threaded end connections, with the purpose of extending the connection of the pipe by installing two different pipes together.

  • Union – Designated with three components that include two bodies and one nut. It is different from coupling as it allows future disconnection of pipes for easy maintenance. 

  • Round Cap – It is used to protect and secure pipe end connection. It has one female end connection. 

  • Hex Bush – Slight different from most fittings as the male threaded size is bigger than the female threaded size. Used for connecting two pipes in different sizes.

  • Hex Plug – Hexagon body type with male connection, installed at the end of the flow direction with the purpose of stopping fluid movement in the overall piping system.

  • Hex Nipple – Designated to extend piping connection by connecting both female sides. It has both male threaded end connections.

8. What does ASME stand for?

Threaded fittings are known to be designated hardware that is created to help connections between pipes and tubes of different sizes and shapes, commonly used in plumbing devices and hydraulics systems to assist in supporting fluid flow. Class 150 threaded fittings are produced with adherence to ASTM A351 CF8M/316 stainless steel, they are also produced in accordance with various standards such as the American Society of Mechanical Engineers (ASME), American Society for Testing and Materials (ASTM), and so on. 

Class 150 threaded fittings can serve as a regulator for low-pressure fluids, they are applied mainly in systems requiring low working pressure such as waterworks, plumbing, oil, gas, etc. Also, these fittings are designed for threaded connection, where welding isn’t compulsory. 

Install: 150




Thread the male fitting with Teflon tape or plumber’s tape which is used to establish a tighter seal to prevent seepage.

150# fittings


Wrap it clean and make sure it is clean of excess application of Teflon Tape.

150# fittings


Tighten the threaded connection using a wrench. However, avoid using excessive strength in screwing, which might cause damage to the fitting or pipe.

Full Coupling 150# 300px.png


Ensure that the size of the fitting is respected to the size of the pipe. Take into consideration that when making a connection, installers have to make sure the alignment is the same.

90D Street Elbow 150# 300px.png

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