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5 inch or 6 inch flue pipe

Updated: October 2026

The stove collar in front of you measures 5 inch, and the amazon.co.uk results also offer stainless tube about 60 mm across. A 5 inch or 6 inch flue pipe is a house-stove decision, and the smaller tube is a different product. The pipe has to be at least as large as the stove outlet, and at least the size in Approved Document J Table 2. The full list of twelve is on our [stove pipe comparison](/hub/fireplaces-and-stoves/stove-pipe). The figures are England's Approved Document J (2022). Wales, Scotland, and Northern Ireland publish their own standards. We did not measure a stove in a lab.

The stove collar in front of you measures 5 inch, and the amazon.co.uk results also offer stainless tube about 60 mm across.

Our top picks

StoveMaestro StoveMaestro 500 mm x 5 inch stove pipe

Best overall

StoveMaestro StoveMaestro 500 mm x 5 inch stove pipe
8.1/10about £29.99
View offer
TAISOCA TAISOCA 60 mm tent stove pipe

Alternative

TAISOCA TAISOCA 60 mm tent stove pipe
6.2/10about £28.99
View offer
PATIKIL PATIKIL 8 inch to 3 inch adaptor

Alternative

PATIKIL PATIKIL 8 inch to 3 inch adaptor
1.3/10about £29.99
View offer
On this page
  1. 1.Read the outlet before the basket
  2. 2.125 mm or 150 mm
  3. 3.What this Amazon set actually measures
  4. 4.Size is not a smoke-control exemption

Read the outlet before the basket

Start with the collar, or the outlet in the stove manual. Five inch is 125 mm. Six inch is 150 mm. Approved Document J, at paragraphs 2.4 and 2.5 and in Table 2, sizes the flue from the appliance. The flue is never smaller than the outlet, so a 6 inch collar cannot take a 5 inch pipe. A fitter might run 150 mm above a 125 mm collar so a later fuel is still covered. That is not a reason to shrink. A Torfaen leaflet prefers 150 mm locally. That is not the England-wide minimum. If you do not yet know the product type, start with our stove flue pipe buying guide.

125 mm or 150 mm

A closed appliance up to 20 kW, on smokeless fuel or as a Clean Air Act exempt appliance, can use a 125 mm flue. A rectangular flue on that row needs a 100 mm side when straight, and 125 mm with bends. Other closed appliances up to 30 kW need 150 mm. The pipe still cannot be smaller than the outlet. A non-exempt 8 kW wood stove sits in the 150 mm row. An exempt badge does not shrink a 6 inch collar. Joint direction, and the ban on single-wall pipe through a ceiling, are on our how to install stove pipe page.
StoveMaestro StoveMaestro 500 mm x 5 inch stove pipe

Testsieger

StoveMaestro StoveMaestro 500 mm x 5 inch stove pipe
8.1/10about £29.99
View offer

What this Amazon set actually measures

The one 5 inch wood-stove length is the StoveMaestro pipe, 500 mm by 5 inch, about £29.99, with 4.6 from 238 reviews. It is a candidate only when the collar is 5 inch and Table 2 allows 125 mm. The listing prints no British Standard and no clearance. It is not a 6 inch pipe. TAISOCA is four lengths at about 60 mm by 320 mm, about £28.99. A review that mentions a small wood stove does not change that bore. A 6 cm Warmhm set and a 75 mm elbow at about £11.79 fail the same test. PATIKIL PCA-8-3, about £29.99 and with no reviews, says 8 inch to 3 inch on one line and 2.54 x 2.54 x 9.14 cm on another. That step is not a way to shrink a house flue.

Size is not a smoke-control exemption

A 5 inch pipe does not put the stove on the exempt list. In a smoke-control area you burn an authorised fuel, or you use an appliance exempt for that fuel. England uses the Defra list. GOV.UK states penalties for England of up to £300 for chimney smoke, and up to £1,000 for buying unauthorised fuel for a non-exempt appliance. Check the stove, not the pipe. A 125 mm flue on a non-exempt stove does not authorise ordinary wood. If the outlet or the exemption is unclear, ask a HETAS-registered installer or building control before you order.

Common questions

When is 6 inch the minimum?
Six inch, 150 mm, is the minimum for other closed appliances up to 30 kW, the ones that are not in the 125 mm row. It is also the minimum when the stove outlet itself is 6 inch. A Torfaen leaflet prefers 150 mm so the stove is covered whatever the fuel. That preference is not the England-wide minimum for an exempt stove with a 5 inch outlet.
What if the stove outlet is 5 inch but the old chimney is larger?
Keep at least 5 inch from the stove, and let the chimney be larger. You connect upwards into the bigger opening with a proper increase in size, if an adaptor is required at all. You do not squeeze the stove down to a smaller pipe. The 8 inch to 3 inch adaptor in this set is a reduction, and its two size lines disagree.
Can I reduce the flue to make a pipe fit?
Reducing the flue below the stove outlet, or below Table 2, breaks the size rule. A camping reducer, or an 8 inch to 3 inch adaptor, does not become legal because it is sold as a chimney adapter. If the pipe is too small, the fix is a pipe at the right diameter after an installer has checked the route.
Is 60 mm stainless close enough?
Sixty millimetres is the camping size in this set, not a near miss on 125 mm. The TAISOCA lengths are about 60 mm by 320 mm. A UK review that mentions a small wood stove does not change that bore. A 6 cm Warmhm set and a 75 mm elbow fail the same test. Use 60 mm only on a tent stove whose own outlet is that size.
Does a 5 inch pipe make the stove legal in a smoke-control area?
No. The pipe is not the exemption. In a smoke-control area you need an authorised fuel or a Defra-exempt appliance used as the exemption requires. In England, chimney smoke can mean a penalty of up to £300, and buying unauthorised fuel for a non-exempt appliance can mean a fine of up to £1,000. Check the stove on the England exempt list. Then check Table 2 separately for 125 mm or 150 mm.

Related pages

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How to install stove pipe: socket up, stay in the room

Sources

Public UK sources and the amazon.co.uk listings in this scrape, last checked on 15 October 2026.

  1. Approved Document J, combustion appliances and fuel storage systems (England, 2022) (retrieved 15 October 2026)
  2. GOV.UK, smoke control area rules (retrieved 15 October 2026)
  3. The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022, SI 2022/707 (retrieved 15 October 2026)
  4. HETAS, when to get a chimney swept (retrieved 15 October 2026)
  5. BFCMA, chimneys and flues (retrieved 15 October 2026)
  6. BFCMA, flue designations (retrieved 15 October 2026)
  7. BFCMA, chimney and flue design (retrieved 15 October 2026)
  8. SFL SVIT installation guide (retrieved 15 October 2026)