What is the difference between L vent and B vent?

It may be difficult to tell the difference between Type L and Type B vents because they are made from similar components, but the vent type should be clearly printed on the vent. Both are double-walled, although Type L vents generally have a stainless steel inner wall, while Type B vents do not.

nachi.org - Type B and Type L Vent Inspection - InterNACHI®

How can I heat my house for free?

10 step guide to keep your house warm without heating Rejig your furniture. ... Use a terracotta heater. ... Invest in insulation. ... Think about...

Last updated Jan 29, 2019

Can you move a fully built shed?

By doing so, you will not need to develop or buy a brand-new shed at your brand-new location. You might believe moving a shed will need you to take...

Last updated Apr 24, 2022

Can I build my own shed?

Yes, with the right plans you can build your dream shed.

Learn More »

Promotion

by Nick Gromicko, CMI®

Type B Vents

Type B vents are vents suitable only for listed, draft-hood equipped, gas-fired appliances, including most domestic heating and hot water systems.

They may not be used with any of the following appliances:

wood-burning appliances, such as fireplaces and wood-burning stoves;

incinerators;

oil-fired equipment;

coal-fired equipment;

any appliance that burns anything other than liquid propane or natural gas; or

any appliance that produces flue gasses that exceed 480° F (249° C).

Type B vents must be equipped with their own special chimney caps. If the cap is damaged or lost, it should not be substituted with something not recommended by the manufacturer. The clearance required from combustible materials is printed on the flue’s exterior metal surface, and is generally 1 or 2 inches.

Type L Vents

Type L vents are designed for venting approved oil-fired and natural-gas appliances that produce draft hood flue gasses that do not exceed a temperature of 570º F (299º C), or 926º F (299º C) for 10 minutes in an over-fire situation. The minimum clearance from combustible materials is generally 3 inches. Type L vents should not be used to vent coal- or wood-fired appliances. It may be difficult to tell the difference between Type L and Type B vents because they are made from similar components, but the vent type should be clearly printed on the vent. Both are double-walled, although Type L vents generally have a stainless steel inner wall, while Type B vents do not. Regardless of the vent type, InterNACHI inspectors may check for the following defects: deterioration of the outer wall, which is likely caused by failure of the inner metal lining; violation of roof clearance requirements. All metal vents must terminate at least 2 feet above the roof surface and anything within 10 feet of the vent, such as the crest of a roof ridge;

missing components, such as a chimney cap;

firestops not installed at either the top or bottom side of the joist where the vent passes through floors or the roof. The firestop should allow a fire-resistance rating equal to or greater than the floor or roof assemblies through which the vent passes;

blocked bird screens, often caused by freezing moisture in cooler climates;

crucial joists, rafters or other load-bearing structural members that have been cut to allow for the vent to pass. Plumbing and electrical lines should also not be disturbed by the vent; and whether the vent is too high or too low. Manufacturers may set minimum and maximum height requirements for the whole vent assembly, such as the AirJet Type L vent, whose minimum height is 6 feet and maximum height is 30 feet. Inspectors may recommend that extra corrosion resistance for vents be provided by a stainless steel cap, stainless steel jacketed pipe sections, or stainless steel or aluminum flashings and storm collars. They may also recommend that clients use commercially available combustion-enhancing, acid-neutralizing fuel additives to prevent damage caused to vents from sulfuric acid. In summary, Type B and Type L vents are designed to vent gasses from specific types of appliances and under certain conditions.

What is the most bought thing in the world?

What is the most sold item in the world? The most sold item in the world is clothing and fashion items. This ranges from women and men's outfits to...

Last updated Sep 20, 2018

What does a White smith make?

The whitesmith manufactures articles of neater and more delicate form, as locks, keys, carpenters' tools, &c. The blacksmith does little with his...

Last updated Nov 1, 2022

Promotion

How do I know what size vent cover to buy?

Measure Vent Covers Remove your existing vent cover. Note: Do not measure your existing cover. MEASURE THE DUCT OPENING IN YOUR FLOOR, WALL OR CEILING. (LENGTH IN INCHES -BY- HEIGHT IN INCHES) THIS IS YOUR DUCT OPENING SIZE. ... Match the duct opening size to the corresponding vent cover size listed on the product listing.

ventandcover.com - How to Measure Your Vent Covers

If a duct opening has restrictions in terms of outside dimensions because it needs to fit inside the limited space of a toe kick, or it is too close to the adjacent wall/ceiling you may require a custom outside dimension. Most of our laser cut metal covers (aside from Quick Ship items), as well as our wood covers can be adjusted to fit the correct border size you require--if you need a custom outside dimension please fill out the custom request form here

Have a Non-standard Size?

There is no need for precise measurements, you can round the measurement to the nearest 1/2" size. e.g. If your duct opening measures 9-3/4" x 9-3/4" a 10x10 cover will work. If your duct opening is rounded to the nearest 1/2" size and you still cannot find your duct opening size listed don't worry. Many of our covers are available in custom sizes. Click here to fill our our Custom Size request form.

New wall or floor trim leaving no space for a standard cover border size?

Don't worry, we can adjust the size of your cover to fit! In many cases you will need to size down the cover to ensure the cover and its accompanying border will fit your duct. This is done by subtracting the size of the border (typically 1"-1.5") from the opening size. e.g. a 10"x4" duct opening that butts up against a wall can be covered by a 10"x3" cover. Please call us if you are unsure of your measurements.