Type B Gas Vent Pipe: Uses, Components & Installation

The most appropriate venting system for gas-fired appliances is the type B gas vent pipes.

The most common gas-fired appliances include stoves, furnaces, water heaters, and many others.

These require a specially designed venting system to enhance the proper discharge of combustion gases and byproducts.

About B Vent Pipe

This venting system tends to be more efficient than others within its category in the sense that it comes with insulation. Such insulation enables it heats up rapidly.

The high temperature is retained for as long as the gas-fired appliance remains in use.

What results is a situation where minimal condensation occurs in both the venting system and appliance.

How Type B Gas Vent Pipe Works

What is a type b gas vent?

A type B gas vent pipe takes out combustion gases that are hot up the pipe system and out through the roof.

Although this sounds quite easy, a type B gas vent pipe’s design is carefully done to enhance insulation. Its double-layer piping ensures less condensation on vent pipe walls as the exhaust travels out.

Flue gases need to be buoyant enough to float out fast. To ensure such buoyancy, much heat needs to be retained. The insulation provided by the vent pipe ensures this is achieved.

Pros and Cons

As expected type b gas vent pipes have their advantages and disadvantages. In terms of advantages, these venting pipes tend to be less expensive to install than others.

Also, there’s the efficient removal of combustion gases from the gas-fired stove or other appliance.

The type B gas vent pipe is not without its disadvantage(s). One of the clear areas of disadvantage is its limited efficiency which is most common when a downdraft occurs in your chimney.

What more?

Recall that we said the type B gas vent stays hot for as long as the gas-fired appliance remains in use. As long as your gas vent remains hot, some heat is lost in the process.

Can Type B Gas Vents be used with Non-Gas-Fired Appliances?

Not at all! These vent pipes are specially designed for use with only gas-fired appliances such as water heaters, space heaters, boilers, gas stoves, and gas furnaces, etc.

These vents are designed for both residential and industrial uses and come in varying sizes.

The type needed for a home is largely influenced by the number of gas-heated appliances available.

Type B Gas Vent Pipe Designs

Type B gas vent pipes are mostly constructed of aluminum alloy which makes up the inner wall and galvanized steel for outer walls. These venting pipes are either oval or round-shaped.

These vary in size and length. The size you’ll need will be determined by your heating appliance.

Round type B gas vent pipes tend to have more size and length variations than oval vent pipes. Typical sizes for round type B vents include 3”, 4”, 6”, 7” and 8”. For lengths, you have 6”, 12”, 18”, 24”, etc.

For oval vents, sizes include 4” and 5”.

Type B Gas Vent Pipe Components

Type B gas vent pipes come with lots of different components each having its use.

These are split into different categories ranging from vent pipe, elbows, tees & wyes, tops, supports & firestops, flashings & storm collar, adapters, as well as connectors & increases.

Under the elbows, tees and wyes are the round pipe, 90° adjustable elbow, 45°/60° adjustable elbows, standard tee, and the fixed wye.

Components belonging to the tops, supports & firestops category include top or bird proof, hi-wind top, support assembly, a wall thimble, and wall support or band assembly.

The gas vent firestop spacer is another component.

Another category of components is flashings and storm collars. Under this is adjustable roof flashing, and the tall cone adjustable roof flashing.

Others are the tall cone flat roof flashing and the storm collar.

For adapters, connectors, and increases, you have a draft hood connector, universal adapters, and appliance increasers. There are also double wall increasers, low profile double wall increasers, as well as the reducer.

Round vent pipes come in varying sizes ranging from 10” through 30”.

Those with adjustable lengths vary from 10” through 18”.

For components under the flashings and storm collar category, you have tall cone flat roof flashing, adjustable flashing storm collar, increase, and draft hood connectors.

  • Oval Pipes

Type B gas vent pipes are also found in oval shapes. Components under this category include the oval pipe, adjustable oval pipe, 45°oval elbow, 45° oval elbow-flat, standard oval tee, and standard oval tee cap.

Others include the 4” oval top, oval vent kit, oval tee support, oval firestop spacers, and type BW hold-down plate.

Uses of Type B Gas Vent Pipe Components

As stated earlier, each component has its use. Without such components, the venting system can’t function. We won’t be discussing all of those listed but will focus on a few.

Such details include;

  • 90° Adustable Elbow

When there are obstructions such as joists, rafters an offset will be necessary to avoid such obstacles. This is where the 90° adjustable elbow comes into play.

It also helps with orienting pipes between horizontal and vertical orientations.

  • 45° & 60° Adjustable Elbow

Like 90° adjustable elbows, the 45° and 60° adjustable elbows also help with navigating obstructions. However, the only difference is in the angles.

  • Top or Bird Proof

This is similar to the chimney cap in the sense that it keeps out debris and rain from getting into the gas vent pipe. However, tops are only used with gas-fired appliances.

It also serves as an external screen that keeps out birds.

  • Wall Thimble

For gas vent pipes that exit through walls, the wall thimble comes in handy to prevent such from contact with combustible materials. It provides a safe clearance as well.

  • Pipe Collar

Pipe collars serve to provide a decorative or finished appearance to your gas vent pipe. This component also doubles as a firestop.

  • Storm Collar

When a weather-proof seal is needed for the vent pipe above the roofline, the storm collar is used for that. It’s installed above the flashing.

There you go! The various functions, designs, and components of type B gas vent pipes have been discussed. We’ve seen that there are two main types, the round, and oval vent pipes.

These aren’t suitable for use with non-gas-fired appliances.

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