What is the difference between a direct vent and a Type B vent?

Author: Prof. Ethan Jacobs I  |  Last update: Tuesday, February 25, 2025

The difference thus far is installation. Direct vent can go out can go out a side wall or outside of your wall. A B vent must always terminate vertical it cannot never terminate out to side wall.

What is the difference between b vent and direct vent?

The biggest difference in B-Vent vs. Direct Vent is that the Direct Vent appliances are sealed to the room.

When should a type B vent be used?

Type B Gas Vent is designed for negative pressure applications and flue gas temperatures not exceeding 400°F above ambient for Category I appliances.

What is Type A vent used for?

The Type A chimney is suitable for use with an appliance that burns gas, oil or solid fuel provided that the temperature of the flue gas does not exceed 540°C (1000°F). A gas vent consists of factory-made metal sections that can be joined together on site.

What is type B pipe used for?

The Amerivent all-metal, double-wall gas vent is listed as Type B by Underwriters Laboratories, Inc. and is approved for such residential and commercial applications as Category 1 water heaters, boilers, furnaces, space heaters, or wall heaters.

B Vent vs Direct Vent Gas Fireplaces and Furnaces

What is the difference between type A and type B pipe?

Ringfit Pipes come in two different classes – “Type A” and “Type B.” Type A pipes are typically used for ventilation and rainwater applications, while Type B pipes are suitable for soil and waste discharge.

What is the difference between Class A and Class B vent pipes?

There are two basic types of chimney pipes: class A and class B. Class A chimney pipes are used solely as an exhaust pipe, while class B pipes feature both intake and exhaust mechanisms. Most chimney pipes are class A, as this class requires only basic venting for internal appliances (e.g., stoves and fireplaces).

What can a Type B vent flue be used with?

Use with natural gas or liquid propane category I and draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent. Applications include: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications.

Can a B vent be used outside?

Outside vents could reduce venting action; therefore, such installations are not recommended.

Which Type B vents shall not be used for venting?

Type B Vent shall not be used to vent flue products from incinerators, combination gas/ oil appliances, oil-fired, or wood-burning appliances. If there is a question about the use of Type B Vents, contact the appliance manufacturer or DuraVent's Engineering Department for further information. 1. Appliances.

Why can't you use B-vent horizontally?

No. Per the sizing tables, all orientations must terminate vertically with a UL listed rain cap, otherwise the appliance may not vent properly.

What category is Type B-vent?

B-vent is ONLY allowed on Category 1 appliances unless the appliance manufacturer has specifically certified a particular B-vent system to be used alternatively.

What is a direct vent system?

A direct-vent sealed-combustion furnace, boiler, or water heater brings combustion air directly from outdoors to the sealed combustion chamber through one sealed pipe and exhausts the byproducts of combustion (carbon dioxide and nitrogen) to the outdoors through a second sealed pipe.

Is direct vent better?

Direct vent fireplaces offer a range of safety features that make them a top choice for home heating. These fireplaces are sealed systems, preventing indoor air pollution and reducing the risk of carbon monoxide poisoning.

How hot does a direct vent pipe get?

Q: How hot does direct vent pipe get? A: Direct vent pipes can get very hot, typically ranging between 300°F to 500°F, depending on the appliance and usage.

What is the vent in the bottom of my fireplace?

A gas fireplace has a bottom vent through which the cool air in the room is drawn into and is then transferred through a chamber that encompasses the firebox. It then connects to a vent at the top. The combustion chamber or firebox is the area of the fireplace in which the fire and heat are generated.

Which is better, direct vent or b vent?

Direct vent is much more efficient, you're pulling fresh air from outside of the house. While you're simultaneously exhausting and gives you more flexibility from an install stand point and most of all direct vent systems are going to heat much better because they are sealed units.

When to use type B vent?

B-Vent, also known as Type B vent or natural draft vent, is commonly used for venting gas appliances that are designed to use indoor air for combustion. These appliances typically have a draft hood to facilitate the flow of air and exhaust gases.

Do you put screws in a B vent?

Although not required under the terms of the UL Listing because of the integral couplers, screws are permitted to be installed at the joints in 3” through 8” vent.

What are the three main types of flue?

There are six main flue types, and each can be determined by simply looking at your roof.
  • Brick Chimney. The Classic brick built chimney is suitable for all gas fires and stoves in this website. ...
  • Pre-Fabricated. Pre-fabricated flues are suitable for most gas fires and gas stoves. ...
  • Pre-Cast. ...
  • Balanced Flue. ...
  • Flueless.

What are the clearance requirements for Type B vent?

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.

How high should B vent pipe be above roof?

The vent pipe should be run up to a point where the top end is at least a foot or so above the roof.

How far can a chimney pipe run horizontally?

If you plan to use an existing chimney, both its location and the length of its flue will be determining factors. Note these guidelines: The horizontal section of the uninsulated stove pipe should not be more than three-quarters as long as that section of the flue above the point at which the pipe and the flue connect.

Are B-vent fireplaces safe?

B-Vent fireplaces are safe, like direct vent fireplaces, the byproducts of combustion are sent outside of the home. There is the possibility a downdraft from the outdoors will travel through the B-Vents piping, but many units have a sensor that will shut off the fireplace if this occurs.

Is a Type B vent used for venting a listed or approved appliance equipped to burn?

A factory-made gas vent listed by a nationally recognized testing agency for venting listed or approved appliances equipped to burn only gas.

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