How Many Fixture Units On A Two-Inch Vent?

By - Ron Singh

Updated -

The size of a vents plumbing must be perfect, especially the fixture units. The reason is that there are many disadvantages to using the wrong size for your vent.

A plumbing system cannot function properly without a well-built vent system. Hence, it is an important aspect to facilitate effectively. In addition, you must know the exact fixture units suitable for each vent’s size.

A two-inch vent can house 24 fixture units and nothing more. This size is perfect for a two-inch vent and will pass the amount of air the plumbing needs. Failure to adhere to the safety protocol will result in a foul smell which is unpleasant if you do not fix the problem.

How Many Fixture Units on a Two-Inch Vent IPC?

How Many Fixture Units on a Two-Inch Vent

The international plumbing code is like any other constitution guiding a sector. It provides the platform for every building and structure to abide by for a correct vent system.

Being familiar with the dangers of not following the rules, they aim to prevent as much damage as possible. Ignoring the IPC guidelines might be due to a few reasons.

  • Trying to play smart and manage materials leads to damage and unnecessary cost in the long run.
  • Another reason is; when you use substandard materials instead of the original.
  • In addition, when you hire an inexperienced company to handle your plumbing.

Of course, the IPC expects every two-inch vent to be in line with a 24-fixture unit. This unit is ideal and does not require any backing.

Even though there are different types of vents, the one you choose depends on your preference, cost, and houses requirement.

IPC has major concerns about the community’s health and wellbeing. If an incorrect vent is left unchecked, it will cause health hazards in the home and community.

Consequently, the IPC should do its job by keeping everyone safe and promoting wellness.

A good vent must be of reliable materials that can trap smell and pass it from the house. Therefore, before you can begin your plumbing, consult the IPC to ensure that you are on the right track.

In addition, it would be best if you only worked with companies that follow each code to the latter.

The first sign that you might be hiring the wrong plumber is if they exceed the maximum number of fixtures.

But, of course, you can only know the maximum number of fixtures if you have done your homework.

A plumbing fixture is the discharge rate per time it is relevant. It would be best if you do a little study on any project before you embark.

This way, you will quickly know when there is an error or wrong quotation. After all, ignorance or oblivion has no advantage.

In the end, you might have sufficient knowledge to handle future projects and discover if there is a problem.

How Many Fixture Units on a Two-Inch Wet Vent?

A wet vent is a two-in-one pipe that serves as an air outlet and a waste line. This type of vent is peculiar to washrooms, sinks, and drains. However, there are strict rules to follow if you employ a wet vent. 

Here are some of them.

#1. The Fixture Is Proportional to the Size

Using the correct material is essential in construction. However, using materials that do not fit leads to damage and accidents in the long run.

Eventually, you may have to spend more to repair the damage you incurred. This rule is also applicable to the vent plumbing system.

#2. The Weight of the Vent Can Allow What It Can Handle

The bathroom and kitchen are the most functional parts of a house because of the inexhaustible water use.

We need water to cook, clean, bathe, and do virtually everything to facilitate housekeeping.

To this effect, wet vents must have the capacity for the amount of water that will pass through the pipes.

You must take extra precautions because wet vents are responsible for air and wastewater. It would be best if you knew that the two-inch unit fixture is best for a wet vent.

This way, it can hold the wastewater and allow air to pass simultaneously. Drain pipes are responsible for transporting water from the drain sinks to the sewer.

#3. Toilet Vents Go Downstream

There is no doubt that you cannot stay in your house if the foul smell from the toilet does not pass correctly.

Consequently, you must ensure that the toilet’s vent is correct to avoid air pollution.

Unlike the regular vents, all toilet vents go downstream and into the sewer. This way, the rate of air pollution is minimal, and we can breathe fresh air.

Amounts of Fixture Units Per Vent

There are different fixture units suitable for each type and size of vent. For example, this article shows that a two-inch vent can house 24 fixture units.

Aside from this, there are other fixture units and the type of vent suitable for them. Here is a table that provides information on the types of vents and the preferable fixture units.

Vent TypeFixture Units
1 ½ -inch vent8 fixture units
2 -inch vent24 fixture units
2 ½ – inch vent42 fixture units

There is a slight difference for wet vents because of their double function, even though it might not be as significant.

The best thing to do is to be certain of the capacity before indulging; this keeps you safe.

In addition, land and water pollution are offenses punishable by law that will cost a fine. For example, you do not want to be the bad neighbor whose lawn smells like rotten eggs.

Methane gas from the pipes can produce a foul odor that is irritating. To make things worse, it is highly flammable and hazardous as it may lead to a fire outbreak.

Now, it is left for you to weigh your options when you do the right thing; which would you rather have? To spend a few extra bucks and hire a good plumber or save cash by hiring a quack and paying for damages later?

How Far Can You Run a Two-Inch Vent?

Aside from having suitable vent housing, it must also follow the proper route. For example, if you have the correct fixture unit to a vent and it runs wrongly, you risk plumbing issues.

The distance between the horizontal and vertical pipes must be correct; not too great. For a two-inch vent, it must be six feet above the ground. This distance is suitable for the air to pass without causing damage.

 There are specific problems associated with faulty plumbing.

  • Corrosion 
  • Leakage
  • Foul smell
  • Clogs
  • Tap, refusing to turn off completely.
  • Toilet refusing to flush correctly.
  •  Pipes are clanging while water is running.

It would interest you to know that besides faulty installation, expected degradation occurs in plumbing. Over time, materials wear and develop unavoidable faults.

However, checking your plumbing occasionally will improve the chances that it will last longer.


In conclusion, a two-inch vent is for 24 fixture units. Plumbing is a sensitive matter that you must tread carefully.

Do not overload the pipes as they harm you and your family. In addition, you can be a good citizen by abiding by the IPC guidelines and saving yourself stress.

Some consequences follow defaulters, and you do not want to know the cost.

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