In this article:
We discuss the properties and uses of plain fittings and threaded fittings within pipework
We answer: What does BSP mean?
This is an introductory article
BSP Thread
All of our threaded fittings on our site are BSP Thread, which stands for "British Standard Pipe". BSP is a thread standard and is by far the most common thread in use in the United Kingdom today. So if you're in the UK and looking to match threads to a fitting that you already have, chances are that you currently have a BSP thread*.
British Standard Pipe thread is always referenced and only available in imperial sizes (Inches and fractions of inches).
That's not to say you can't go from a metric pipe to a BSP thread, any metric "Plain x Thread" fitting on our site will be categorised as an adaptor as it would take you from metric to imperial thread.
The thread can either be on the inner diameter of the fitting which makes a female thread or it can be on the outside of the fitting or pipe which forms a male thread.
Female threads accept another fitting with a male thread and Male threads accept fittings with female threads, this is known as mating the threads.
Whenever a threaded joint is being made, the use of PTFE tape wrapped around the male thread before mating should create a pressure resistant leak-free joint.
Advantages of threaded fittings:
• Relatively easy to disconnect components after installation
• Allows connection of components of different materials
See our range of BSP Threaded PVC fittings
Plain
Plain refers to the fact that there is no thread on the fitting.
In the case of PVC and ABS pipes and fittings: the pipe and fittings are designed to be cemented together to form a pressure resistant bond and leak free joint.
Cemented joints are very common in PVC & ABS pipelines across the world. Generally the pipeline would be constructed mostly of cemented joints with threaded fittings used for outlets or connection points allowing the quick connection and disconnection of components such as pumps.
Throughout our website any fitting that is described as Plain, will be entirely plain on both ends. You may see "Plain x Thread", which means the fitting is plain on one end for cementing, but has a thread at the other end to accept a threaded fitting. These are common in pipework as they facilitate the introduction of threaded components onto a cemented system that would otherwise have plain ends.
More information on making cemented joints
Advantages of plain fittings:
• Ease of installation in the field without the need for workshop tools to make threads.
Disadvantages
• Cannot easily be disconnected for repair or replacement
• Connection only to like-for-like material
See our range of solvent cements |
See Plain PVC fittings
Whilst above we have compared Plain & Threaded fittings to illustrate each of their properties and usages, many piping systems require both types and each should be considered individually for their intended uses. For example; the majority of the pipework is usually connected by cemented joints and then the outlets and connection points might be threaded to allow the easy removal of plugs or for the quick removal of interchangeable components.
*Other types of threads such as ASTM (American Standard) are in use in the UK, but they really are much less common within the UK pipe industry. Maybe if you've imported something or ordered something over the internet that is made for the US market then the likelihood of it being ASTM is much greater. We DO have stocks of ASTM threaded fittings, but don't have them on our website, if you're looking for ASTM thread then please give us a ring.
This is a very brief overview of the meaning of the terms "Plain", "Plain x Thread" & "BSP", and there is much more to know on each of the subjects that we have touched on. There may be exceptions to the information given but we cannot go in to so much detail in one general introductory article, and therefore this article is not to be treated as a definitive guide.
Summary:
• BSP Stands for British Standard Pipe and is the most common thread standard for pipework in the UK.
• Plain fittings refers to the fact that the fittings have no thread
• Plain fittings in ABS & PVC
are designed to be jointed with solvent cement
• Threaded fittings facilitate the connection to other materials such as brass taps in a system composed of plastic pipework