W Tombling Ltd - activair
 about W Tombling Ltd - activair How to contact us Please send me a quotation sign up for our free activair newsletter


Ducting Homepage
What is polythene ducting ?
Why use polythene air ducts ?
Polythene layflat ducts - sizes and quotations
Designing an inflatable duct system
Duct kit and installing air ducts
Ducts - frequently asked questions
HVAC ducting - uses of inflatable ducts
Polythene air conditioning ducts
Polythene heating ducts
Polythene ventilation ducting
Air duct for displacement ventilation
Plastic ducting for destratification
Polythene ducting in glasshouses
Flexible ducts in mushroom farming
Plastic ducts in temporary structures
Fabric ducting and ducts
Textile ducting and ducts
Flexible ducting
Flexible air ducts and sick building syndrome

Search this site:

Using : 
All Words 
Any Words

W. Tombling Ltd.

Wembley House
Dozens Bank
West Pinchbeck
PE11 3ND

+44 (0) 1775 640 049

+44 (0) 1775 640 050


ductsActivair ducts --------------

Activair polythene ducting - faq

What is polythene ducting?

The Activair ducting system is the most simple, efficient and cost effective method of conveying warm and cold air from place to place, and distributing it where required.

Activair polythene ducting is an inflatable duct system, it is not self supporting and relies on the air pressure within the duct to inflate and support it. For maximum performance the airflow and duct size must be carefully matched, see designing an inflatable duct system for details.

I have a 10 inch square air outlet what diameter duct do I need?

The outside perimeter of the outlet will be 4 x 10 = 40 inches. You need a layflat size that is half of this i.e. 20 inches. Use 20 inch layflat (12.75 inch diameter).

Do you have a dealer/stockist in the USA, Australia, China, etc.?

We supply all orders for polythene ducts direct from our UK factory. Every polythene duct is individually designed and manufactured to meet the customers requirements, it is therefore impossible for dealers/stockists to hold stock. Using express freight carriers we are able to deliver to most countries within 7 days.

Do your polythene ducts stretch to accommodate the air outlet?

No polythene ducting does not stretch. Use the next biggest size duct, or fit a reducer to the outlet.

Do you make polythene elbows, duct reducers, splitters etc.?

Use metal ducting

I need to thread a duct through some supports or a tight space

Use flexible ducting.

Which way round should perforated ducts go?

The holes should be closest together at the air inlet. This is not a misprint!

I'm looking for textile or fabric ducting

We only manufacture polythene ducting. For most applications it is a direct replacement for fabric and textile ducting. See Activair air ducts for details.

Can I use polythene ducts in my home?

Polythene ducting is intended for commercial and industrial use. You may be able to use in domestic applications, but check your local building regulations first.

Can I use your polythene ducting for suction?

No polythene ducting needs positive air pressure to inflate. Use flexible ducting.

Why are some of the holes in the duct out of alignment?

We do everything possible to minimise this. However it does sometimes happen where the hole spacing changes, it has a negligible effect on the air distribution.

I don’t know the CFM of my fan, can you manufacture a perforated duct?

No, without the cfm we are unable to calculate the correct size, number and position of the perforations.

How do you suspend your polythene ducts?

We supply duct kits which contain the basic items required to support an overhead duct, one is needed for each duct. If they does not meet your needs, contact us, we can supply them with different contents.

Please send someone to see me, or design a duct system for my factory/workshop/warehouse etc.

We are a manufacturer and distributor of hvac products, we don't design or install systems, and consequently don't have sales engineers on the road.

We have put all the information necessary for you to design and install our ducts on this site, and will be pleased to answer any specific questions you have.

However if you are still not sure how to proceed you should contact a local HVAC contractor, or check our dealer locator to see if there is one near you.

What air flow can your polythene ducts accommodate?

See designing with Activair ducts for details.

How do I install your polythene ducts?

See installing Activair ducts for details.

My ducts are splitting after a few months, what's wrong?

The most likely cause is too much air, recheck your CFM per duct and compare it to the recommended figures. If this is not the problem, check for excessive flapping of the duct when inflated (caused by air turbulence - fit an air straightener) or popping as the duct inflates (caused by fan start-up - fit a soft starter to the fan motor).

Can you send me a brochure, leaflet or catalogue?

Printed sales literature has many drawbacks:
Environmentally unfriendly - Forests are destroyed to make paper, and bleaches are used to whiten it.
Wasteful - Sales literature is often read once and thrown away.
Expensive - Leaflets, brochures, etc. are expensive to print and post.
Rapidly out of date - By the time sales literature is printed and delivered it can be out of date.
In comparison sales literature delivered in electronic form has instant global reach, is always upto date, inexpensive and causes no damage to the environment. We therefore only distribute sales literature in PDF format. You will require Adobe Acrobat Reader to open, read and print it.

Acrobat Reader is a free download from Adobe's website.

Where you see the PDF logo pdf logoon this website, you can download printer friendly documents.

If you found this page useful, please take a moment
to tell a friend or colleague about it.

Copyright 2004/6, W. Tombling Ltd.