Spiral duct is created by compressing a coil of galvanized metal into a rigid steel tube. The duct is formed from one complete piece then cut to length, it maintains a smooth internal surface by having no seams, minimising air resistance within the duct run. The lack of seams reduces pressure ...
Spiral duct is created by compressing a coil of galvanized metal into a rigid steel tube. The duct is formed from one complete piece then cut to length, it maintains a smooth internal surface by having no seams, minimising air resistance within the duct run.
The lack of seams reduces pressure within the system and increases both the efficiency and lifespan of any extract or supply systems. The ridges greatly increase its strength and rigidity, whilst maintaining minimal weight.
Where to buy spiral ducting
i-sells.co.uk has one of the largest selections of spiral ducting and fittings available in the UK.
How to join spiral ducting
Spiral ducting is “female”, so can be “push-fit” connected to fittings such as bends and tee pieces as these are “male” and will slot inside the female connection points. You can extend duct runs by joining two lengths together with a “male” connector piece. Place the connector into one end of the spiral duct, then press another length onto the other side, they will slot together. This can be joined with an acrylic based sealant or caulk to prevent leakage. I-sells supplies “safe” galvanised ducting connectors which have a rubber seal to prevent air leakage even further. This is the most cost-effective and time-efficient way to connect and join metal ducting.
How to cut spiral ducting
Spiral ducting lengths can be cut to desired lengths with the use of manual tools such as “Snips” or “nibblers”, or with mechanical metal sheers. Whilst hand tools are cheaper, you may find that the ducting needs to be sanded down or require other finishing processes before it can be correctly installed. Mechanical sheers can be faster and give a neater finish, but this is up to the installer’s preference.
How to install spiral ducting
Spiral ducting is usually suspended horizontally to joists with the use of suspension and split rings supported by banding, studs or with wire and gripples. However, it can also be installed vertically by securing split or support rings to a vertical surface. Ensure adequate support of the ducting is achieved whilst installation, as, without this, bending could occur which may lead to pressure loss and eventual damage to the components.
Sizes i-sells supplies spiral ducting in sizes ranging from 80-1120mm diameter, and 1 to 3m lengths. Custom sizes can be manufactured depending on the requirements of your project. If needed, you can alter the size of your ducting by following the cutting directions below.
Spiral ducting fittings
Our galvanised pipe fittings are considered “male” and will fit inside “female” spiral ducting lengths, and so are considered “push to connect fittings”. Pipe bends, pipe connectors, pipe caps, vents, cowls, male and female couplings, reducers etc can be easily joined to lengths of spiral ducting with a simple push-fit connection. It is advised that the joints be sealed with either duct tape, acrylic sealant or caulk to ensure minimum pressure loss due to leakage. i-sells provides “safe” versions of all metal fittings, these feature a rubber seal that provides a tight seal when pressed into a length of spiral ducting, requiring minimal use of duct tape or sealant, an additional benefit is that these fittings can be easily altered without requiring removal of tape or sealant.
Spiral ducting grilles and access doors
i-sells supplies spiral ductwork grilles and access doors in a wide range of sizes and diameters. They are installed by using a drill to create a pilot hole, then using snips, nibblers or a jigsaw to create the aperture required to fit the grill or access door. The use of safety gloves is heavily recommended when cutting metal ducting, as the edges can become very sharp. Place the grille or access door into the aperture with the grille or access door facing outwards. Use screws to secure into place and use sealant or caulking to prevent pressure loss.
Reducing Spiral Ducting
Should you require to increase or decrease the diameter of your duct run, you can use a reducer to do so. Reducers are male and will fit into female spiral ducting lengths with a push-fit connection. Use of either duct tape or sealant/caulking is recommended to prevent air leakage/pressure loss. i-sells provides “safe” metal reducers which feature a rubber seal that prevents leakage without the need for either tape or sealant. This also allows alteration without removal of tape or sealants. Reducers come in both eccentric and concentric varieties.
It is important to note that either increasing or decreasing the diameter of your duct run will alter the pressure within the duct. This can affect the efficiency of the run or add additional strain on ventilation fans connected to the duct. It is therefore recommended that you contact either the manufacturer or a ducting installation specialist to help calculate the appropriate reduction/increase that your ventilation systems can accommodate.
Spiral ducting weight
Weights can vary by manufacturer, but for reference, i-sells has the following weight for spiral ducting lengths.