Fittings FAQ

General Fittings Information

Q: "What are fittings?"

Q: "What are accessories?"

A fitting is basically an adapter for pipes or parts of a machine. It's used to join two or more things together and will be used to carry gasses or liquids.

Fittings might also be called joiners, couplings, connectors, as well as other similar things.

Fittings can be either permanent (screwed onto something) or quick release types (that can be 'clicked' together, or 'unclicked').

Because fittings join things together, there are 2 ends to each of them and each end is usually described separately. For this reason many fittings have a double description, such as 'Mini Endstop with MALE thread 1/4"'.  In reality this is two descriptions in one: it's a 'mini endstop' and it has a '1/4" male thread' on the other end.

Fittings can have on one end or both:

Threads (either male or female)

Quick Release (male or female, and with or without a mechanism that stops the flow when the fitting is not plugged together)

Hose Barb

Push-In

Hopefully this page will help you to know and understand the descriptions.

Accessories are (sorry girls) not bling or other jewellery. They are small bits and pieces such as hose clips and PTFE tape and are used when joining parts together. Boring right?

Screw Threads

Q: "What is a screw thread?"

You know what a screw looks like right? The things used to assemble IKEA furniture and hold shelves on walls? Well the official name for that twist pattern on the screw is screw thread.

Screw threads are always either:

MALE: Where the thread (twist pattern) is on the outside of the fitting

FEMALE: Where the thread (twist pattern) is on the inside of the fitting

Therefore only a male thread and a female thread can be screwed together.

Both plastic or metal fittings can have screw threads.

Screw threads will only work together if they are of the same size and type. ⇓ See below for more information.

Screw threads are a complex topic and there are hundreds of kinds of them but for our purposes the information on this page is probably all we need to know. What a relief!

As noted above, most fittings that have a screw thread on one end will also have something different on the other end.

Q: "What does BSP mean?"

Q: "What does NPT mean?"

BSP means 'British Standard Pipe' and refers to a screw thread range designed years ago for plumbing in this country. All measurements are in inches (using the " symbol) and the size mentioned refers to the inside diameter of a fitting with that size thread. Make sense? So if you have a pipe with a 1" BSP male thread on the outside of it, the 1" is referring to the inside diameter of the pipe, not the outside diameter of the screw thread. Therefore, the actual outside of the screw thread itself will be larger that 1" when you measure it. See the ⇓ sketch below to clarify this.

A 1" BSP male thread will fit a 1" BSP female thread.

Screw threads will only work together if they are of the same size. So a 1" BSP female thread can only work with a a 1" BSP male thread.

NPT stands for 'National Pipe Taper', and is the most common U.S. standard for pipe fittings. Like BSP, NPT fittings are measured on the internal diameter of the fitting and in inches. NPT threads are very similar to BSP ones.

NPT and BSP can sometimes be made to work together but they are in fact different. Usually only plastic ones can work because plastic distorts and absorbs the small differences as you screw the fittings together. The worst thing to do is screw together a metal fitting from one range and a plastic fitting from the other. Doing this will mean the metal one destroys the plastic one, irreparably.

These are the most common things to look out for:

Shurflo pumps have NPT threads

Shurflo strainers have NPT threads

Shurflo wingnut fittings have NPT threads

SOME filter housings have NPT threads SOMETIMES, depending on the batch (fiddly eh?)

Pretty much all else have BSP threads.

Q: "My fittings don't seem to fit your ones. Why?"

Q: "Do your fittings fit my system?"

Q: "I need a fitting halfway between two sizes of your fittings!"

Although BSP and NPT threads and fittings are the most common in our world of window cleaning, they are not the only kinds of screw threads in existence. After BSP and NPT the most common are Metric screw threads. Many items built in Europe, or for Europe use metric threads on fittings. Some EU standardisation laws have been enforced on things as daft as garden taps and this can cause issues with the BSP tap connectors we sell.

Common items that can have metric threads:

pressure washers ⇘ or pressure washer lances which often seem to have a mixture of BSP or NPT and metric threads

Hose reels

Backpacks

All kinds of DIY stores type 'cheap cheap' equipment

IBC tank outlets

Q: "Can I screw metals fittings to plastic ones?"

The short answer is yes but it's not recommended.

You can do it only if you are very careful and the threads are both of the same family (BSP or NPT).

Getting this wrong in any way will result in damage to one or both of the fittings. That results in leaks or things blowing apart under pressure. It also means that if you ever need to change something you will not be able to because the thread will be too damaged to work a second time.

It is very easy to cross thread the fittings when doing this.

Q: "What does Cross Threading mean?"

When screwing parts together you have to ensure the parts are exactly in line with each other. This will allow the threads to fit together correctly.

If the threads are not lined up correctly they will cross thread, meaning the 'teeth' of the threads do not fit together as they should. This means they will become damaged if you force them together.

Usually only one side of the cross threaded joint is damaged by this action, whichever is made from the softer material. For this reason plastic fittings are more likely to cross thread than metal ones are.

Usually cross threading something causes damage that is irreparable and it makes the parts un-salvageable.

Q: "Why do I need PTFE tape?"

Q: "Why do I need washers in these joints?"

Q: "Why do my fittings leak?"

There has to be a small gap between the threads of two parts screwed together. This is to allow them to move. No gap means they are so tight you cannot turn one against the other to tighten them up. This small gap will allow water or gas to leak from the joint. This is where PTFE tape comes in. It is wound around the male thread of the joint and then it gets squashed and compressed when the parts are screwed together. In doing this it fills up all the small voids between the fittings and seals the gap. If there is still a leak it probably needed more PTFE or the parts were cross threaded and so the joint wasn't correctly lined up.

Some fittings are designed to use a rubber seal, or washer, to close all gaps. Fittings like that are supplied with this washer already fitted. This usually does the job of sealing all the gaps with no need for anything else to prevent leaks. An example of this is the BHC90 we sell.

Parts with washers are usually designed to be done up hand-tight only. Overtightening them will usually deform the washer and actually create leaks! Sometimes the washer can even get squeezed right out of place and end up getting washed away by water!

Quick Release Fittings

Q: "What are Quick Release couplings?"

Sometimes called 'quick connect fittings', 'quick release couplings', 'click fittings' or even 'Rectus fittings' (after a well known brand name), or 'Ezy-Snap' couplings, these are a kind of fitting designed to be joined together or taken apart quickly and without the need for tools or screwing anything to anything. To do this they have special shapes a mechanism to lock them together and seal them against leaks. Usually there is a collar that can be pulled back to release the connection.

Quick release fittings that work together are always a male and a female.

Due to the precision required for them to lock and seal consistently they are made in matching ranges and parts from one range will not work with parts from another range. Another name for range is 'Series'.

Like screw threads, quick release fittings are available in many forms and variations and are used in many industries. In window cleaning we use only a few types and this is already complex enough to confuse many customers.

The male fittings for quick release connections are also sometimes called a 'bayonet' or a 'quick release male adapter'.

The female fittings for quick release connections are also sometimes called 'endstops'.  

Q: "What is an Endstop?"

This is the female side of the quick release connection. This is the part with:

The locking mechanism to keep the connection closed when in use

The collar to pull back when opening the connection

The seal to make sure the connection doesn't leak

Endstops are a type of female coupling that also has a special valve inside it. This valve is always closed until you plug the male into it, a process that opens the valve. This is why they are called 'endstops', because when unplugged they literally do 'stop the end' of a hose and prevent anything flowing out of it. There are some female connections that do not have this valve mechanism in them so they are not technically 'endstops' although they look like them. But pretty much all the metal fittings we sell are endstops. All the female fittings in the 19 SERIES, 21 SERIES and 26 SERIES are true endstops. 

Q: "What is a male quick release fitting?"

The corresponding male part of the fitting

Q: "What is a 'series'?"

A fitting series is the range of quick release parts that are compatible with each other. Within a range, or series:

Any part with a male quick release end will have an identical male quick release end to all other male quick release ends

Any part with a female quick release end will have an identical female quick release end to all other female quick release ends

ALL the male fittings will fit ALL the female fittings

Fittings from one series are not compatible with those of another. This is important and the main reason for returns of Quick Release fittings!

The fittings we sell in series are:

19 SERIES (always metal fittings)

21 SERIES (always metal fittings)

26 SERIES (always metal fittings)

Hozelock SERIES (usually plastic but sometimes partly metal or even entirely metal fittings)

'Slick-Connect' couplings

Q: "What are 19 SERIES couplings?"

19 SERIES fittings are among the largest of the metal quick release fittings used in window cleaning. They are usually made from steel and then covered in some funny coloured metals.

19 SERIES fittings can be used for garden hose (1/2"), minibore hose (8mm) or microbore hose (6mm) by selecting the right size Hose Barb.

Originally they are made for air uses but window cleaners use them for water. This makes them go a little unreliable at times because the water can gradually wash out the grease from the mechanism and this causes them to seize. They are not as prone to this as the 21 SERIES fittings but it can still be an issue.

If dropped or dragged along the floor repeatedly the female 26 SERIES fittings can develop faults such as breaking or seizing up although this is far less common than with the 21 SERIES.

19 SERIES fittings will only plug to other 19 SERIES fittings.

19 SERIES fittings are used in various forms and we sell many but not all of them.

Our 19 SERIES fittings are not the 'Rectus' brand. They are compatible with them.

Q: "What are Mini couplings?"

Q: "What are 21 SERIES couplings?"

Sometimes also called 'Ezy-Snap' fittings, 21 SERIES fittings are the smallest of the metal quick release fittings commonly used in window cleaning. They are usually made from brass and then coated with nickel, making them look silver when you see them.

21 SERIES fittings can be used for garden hose (1/2"), minibore hose (8mm) or microbore hose (6mm) by selecting the right size Hose Barb.

Originally they are made for air uses but window cleaners use them for water. This makes them go a little unreliable at times because the water can gradually wash out the grease from the mechanism and this causes them to seize.

If dropped or dragged along the floor repeatedly the female 21 SERIES fittings can develop faults such as breaking or seizing up.

21 SERIES fittings will only plug to other 21 SERIES fittings.

21 SERIES fittings are used in various forms and we sell many but not all of them.

Our 21 SERIES fittings are not the 'Rectus' brand but they are compatible.

Q: "What are HP couplings?"

Q: "What are 26 SERIES couplings?"

Q: "What are 25 SERIES couplings?"

26 SERIES fittings are among the larger of the metal quick release fittings used in window cleaning. They are usually made from plain brass.

Just to confuse everyone and everything, there also exists a fittings series called the 25 SERIES. These are pretty much identical to the 26 SERIES ones and they are fully compatible with each other. To save confusion here let's use only the 26 SERIES as a reference.

26 SERIES fittings can be used for garden hose (1/2"), minibore hose (8mm) or microbore hose (6mm) by selecting the right size Hose Barb.

Unlike the 21 and 19 SERIES fittings, the 26 series range ARE made for liquids. This makes them by far the most reliable metal quick release couplings.

If dropped or dragged along the floor repeatedly the female 26 SERIES fittings can develop faults such as breaking or seizing up although this is far less common than with the 21 SERIES.

26 SERIES fittings will only plug to other 26 SERIES fittings or other 25 SERIES fittings.

26 SERIES fittings are used in various forms and we sell many but not all of them.

Our 26 SERIES fittings are not the 'Rectus' brand. but they are compatible with Rectus 26 fittings.

Q: "What are Hozelock SERIES couplings?"

Hozelock SERIES fittings are nearly always plastic although a few of them do have metal parts on them or are entirely metal.

Originally they are made for garden uses but window cleaners use them as well for some things. They are convenient and reliable although they can be prone to dripping at times. Of course, this is not an issue when you use them for watering flowers, as designed, but drips inside a van are not so welcome!

Hozelock fittings are only designed for garden hose (1/2").

The Hozelock fittings are unique in our world in that the male (bayonet) has the rubber seal on it. All the other fittings have an internal seal inside the endstop.

If dropped Hozelock fittings can crack. To help with this the some can have rubber on them. If it is a constant problem then maybe the metal ones would be a better solution for the customer.

Hozelock fittings will only plug to other Hozelock fittings.

Hozelock fittings are available in various forms and we sell most of them.

Our Hozelock fittings are not the actual 'Hozelock' brand. They are compatible with them and are an excellent quality.

The rubber on the male ends of the Hozelock range of fittings can split or just deform and start leaking over time.

Generally the best advice is that the customer should use Hozelock fittings all from the same manufacturer. This greatly reduces issues with leaking.

Q: "What are Slick-Connect couplings?"

Yet another brilliant development from the excellent 'Exceed Innovation' company, Slick-Connect fittings are the first fittings made exclusively for window cleaning.

They are made entirely from plastic and have an enclosed connector.

They have a number of advantages over the metal fittings more commonly in use:

The water connection is clear of the ground so it doesn't get damaged when being dragged;

The outer shape of the couplings is angled and that makes them slide over objects on the ground easily, rather than getting snagged on things;

The locking mechanism is very simple on these fittings so there's less to go wrong;

They're quick to fit on your hoses;

They're colourful, meaning they're less likely to get stepped on or to trip people over;

They're quick to use.

Hose Barbs / Hose Tails

Q: "What are Hose Barbs?"

Q: "What are Hose Tails?"

These are parts of a fitting designed to be pushed inside the end of a piece of hose and then locked with a jubilee clip or other hose clip (see below).

They have a ribbed, or separated outer surface so the hose can grip them very well. The same pattern is good for helping the hose seal to the barb and prevent water leaking out between the hose the the barb.

The hose barb is only one end of the fitting. The other end will be something else as noted at the start of this page.

The inside diameter of the hose barb has to be the same as the inside diameter of the hose you are using it with. This means that a 6mm hose barb has to have a minimum of 6mm inside diameter and be used with a 6mm hose. That means they are tight in the hose but also the fitting does not restrict the water flow. 

Hose clips are circular clamps designed to lock hose onto the hose barbs. There are two main kinds:

'Jubilee Clips' have a screw to use when tightening them up. You can also loosen and re-use them. As they are tightened up they usually end up with sharp bits sticking out of them so you can easily get hurt using these. For this reason we don't always use them on hoses that will be handled a lot. They are usually adjustable to fit various hose sizes.

'Ear clips' (as many customers call them) are available in many sizes and slip over the hose before you pinch the 'ears' to close and lock the hose-hose barb joint. They don't get sharp corners on them so are nicer on places you hold in your hand often. These clips cannot be re-used - you have to cut them to get them off again. They are very limited in hose sizes so it's important a customer chooses the right size to start with.

To ensure a good fit customers need to use these sizes of clip:

5mm tubing needs to have hose clips in the range of 7 - 9mm

Reinforced tubing need have hose clips in the range of 9 - 11mm

Microbore needs to have hose clips in the range of 11 - 13mm

Minibore needs to have hose clips in the range of 13 - 15mm

Garden hose needs to have hose clips in the range of 17 - 19mm

Valves / Taps / Tap Assemblies

Q: "What are Valves?"

Q: "What are Taps?"

Q: "What are Tap Assemblies?"

Valves are special fittings for turning the water on or off. The ones we sell can be:

Ball Valves

Gate Valves

Needle Valves

These descriptions refer to the way in which the valve works.

Some valves are also available as:

Long Handle

Short Handle

Butterfly

These descriptions refer to the kind of lever the valve has.

'Tap' is another name for a 'valve'.

A Tap Assembly is a kind of valve that we put on a hose. They are used for stopping water going up the pole.

Microbore / Minibore Fittings

Q: "What are Microbore fittings?"

Q: "What are Minibore fittings?"

Basically, on our site these are EITHER:

Fittings commonly used with microbore or minibore hoses

The hose barb size only

Plastic Fittings

Q: "What are Plastic fittings?"

See them grouped together on our site.

Now that you have ploughed through this page to get here there's very little to say about plastic fittings. Except that they can be pretty much any kind of fitting and are made from plastic. Have a look at the website to see them and it should all make sense. Hopefully!

Metal Fittings

Q: "What are Metal fittings?"

See them grouped together on our site.

Just like plastic fittings except made from metal. Have a look at the website to see them and it should all make sense. Hopefully!

Push-In Fittings

Q: "What are Push-In fittings?"

See them grouped together on our site.

Push-in fittings are little different to the rest. Sometimes called 'compression' fittings, they work on a different principle.

The push-in part has a small inlet with teeth and a rubber seal inside. As you push the tubing into it the rubber seal closes any gaps to prevent leaks and the teeth grip the tube to stop it pulling it again. The higher the water (or air) pressure inside the joint the tighter they hold. To release the tube again you have to press down the collar to release the teeth and allow the tube to pull out.

Push-in fittings can only work with rigid Push-in tubing.

To use the softer Standard Pole Tubing or Reinforced Pole Tubing with a push-in fitting you need to use a push-in male stem. One end of this fitting has a hose barb and the other end is a special shape to fit into the push-in fitting.

The tubing size for Push-in fittings is critical. For instance, some tubing is made to metric sizes and others to inch sizes. A 1/2" tube (which equals 12.7mm) might not fit a 12mm push-in fitting even though the difference is very small. If you do manage to get the tube in you might not get it out again. On the other hand, putting a 12mm tube into a 1/2" push-in fitting might mean it doesn't lock or seal at all because it is too loose.

Push-in fittings can be used over and over but they are not really designed to be. They usually scratch the tubing or stem being put into them and this can cause leaks over time.

Miscellaneous Fittings Items

Q: "What are Miscellaneous fittings?"

See them grouped together on our site.

These are just all kinds of bits and pieces that don't go into any of the other sections.

In the midst of this page you will notice:

Hose clips

PTFE tape

Replacement rubbers for Hozelock fittings