16 August 2018
Valves are devices that control the flow of fluids (liquids, gases, vapors and more) by stopping, adjusting or allowing the passage of the fluid through its container. There are many types of valves available on the market and choosing which one to use in a Revit project can be demanding. As an MEP engineer you have to take into account several technical properties of the valve, as well as the manufacturer that provides it, and combine these criteria with the preferences of the other project stakeholders.
After going through this article, you will have a complete set of correct arguments and useful knowledge to support your decisions regarding the valves you want to use in your Revit projects.
Manually vs. mechanically operated valves
Manually operated valves feature a handle that can be switched to an "on" or "off" position or rotated. Mechanically operated valves are controlled by an actuator attached to them. An actuator is needed for instance in the case when the valve is too large to be operated manually because of its dimensions. You will also need an actuator to control the valve automatically or remotely, such as in washing machine cycles or a centralized control room. Valves controlled by actuators are usually referred to as motorized valves. If you want to use these in your projects, you can download motorized valve Revit families
from the MEP content library.
There are also several kinds of actuators to choose from. For example, electric motors and solenoids fall into the category of electromechanical actuators. Pneumatic actuators are controlled by air pressure and hydraulic actuators are controlled by the pressure of a liquid. View here the library of solenoid valve
Revit files and electromechanical actuators
There is generally not much debate about when you should choose an actuator-controlled valve or a manual one. Actuators are designed to provide comfort, safety and convenience by automating certain tasks and taking into account a number of factors before sending a command. In all other cases, a manual valve will be enough. Unless you have a huge number of valves in a building for which automation is a necessity.
Different types of valves
There is however some confusion when it comes to valve types and the best option for certain situations. Let's take a closer look at the most popular types of valves out there and their best usage.
The closing element of this type of valve is a metal gate
. When the valve is set to the "off" position, the gate is fully lowered allowing no fluid to pass through. When the valve is "on", the gate retracts into the body of the valve. This ensures no or a negligible flow loss across the valve.Best usage
: When the valve is meant to be kept either fully open or fully closed. Keeping a gate valve partially open poses a serious risk of erosion of the gate. The vibrations resulted from the interaction of the fluid with the partially open gate also represent a damage factor.
The fluid flow inside a globe valve follows an S-shaped trajectory
. This means that in a fully open position the fluid has to change direction twice inside the valve. This results in a significant drop in pressure. Therefore, globe valves are not typically used when the flow in the pipe needs to be able to reach maximum capacity. Best usage
: In throttling situations or when frequent operation is foreseen. Globe valves are available in tee, wye and angle patterns
and are many times used for cooling water systems.Best not to use
: When dealing with large fluid pressures because globe valves require enormous amounts of force when opening and closing the valve.
Ball valves are designed to control, stop or allow the flow of fluids through the pipes by means of a sphere contained inside. When the valve is closed, the ball completely obstructs the passage of the fluid. When the valve is in the on position, the ball does a quarter turn (90 degrees) and the fluid is allowed through a cavity inside the ball. These types of valves are in general more durable and easier to use than globe or gate valves and have a low pressure drop. They are known for their perfect sealing capacity
, allowing no leakage when in an "off" position.Best usage
: When a tight shutoff is required such as in the case of gas pipes when a potential leakage could be harmful. They also deliver best performance when they are kept either in an on or off position and are easily maneuverable. Best not to use
: Ball valves are not the best option to use in throttling situations because the seats are prone to damage when exposed to constant wear. Also, as they close, ball valves retain some of the fluid within the inside of the sphere. This can cause the valve to break in case of freeze. Some insulation parts around the valve can resolve this issue when the valve is used in places with low temperatures. You can apply this knowledge by downloading ball valve Revit families
for free here and placing them in your piping system.
Automatic balancing valves have the purpose of restoring the correct hydraulic levels
in heating and cooling systems. Often these kinds of systems have differential pressure changes caused by different valves being opened and closed based on the demand for heat or cold air. Balancing valves will control the functioning of the system by restoring the values that were determined in the design phase. Best usage
: In heating and cooling systems in order to ensure the correct functioning of the system and to avoid important pressure changes. A balancing valve
will ensure an even heat distribution which reduces noise and unnecessary energy consumption.
Butterfly valves are amongst the most popular types of valves. They control the flow of a fluid by means of a rotating disc. Even though they are in certain ways similar to ball valves, butterfly valves are typically easier to install
because of their reduced weight. They are also more precise and can close faster and easier, especially when controlled automatically.Best usage
: In industrial settings when a very precise operation of the valve is required. Moreover, butterfly valves do not require such a solid support structure as ball valves thanks to their reduced dimensions.Best not to use
: When pressure drops could be an issue to the functioning of the piping system. Even when fully opened, the disc of the butterfly valve is in the way of the flow of the fluid, which causes a pressure drop.
Also known as non-return valves, check valves allow fluid to go in one direction but prevents it from going the other way. When the high pressure reaches a certain preset limit, the valve will fully open, allowing clear passage of the fluid, and it will close when it detects fluid coming from the other direction. Check valves are usually not operated manually, as they function automatically based on how they are manufactured and configured. They can however feature a stop-check which allows the operator to stop the flow in one or both directions. Revit check valve families are available for download here
: Check valves are many times used in combination with pumps. In case the pump fails, the check valve will mimic its function, preventing the whole system from malfunctioning. Another common use of check valves is in the household application. Sprinkler systems
can benefit from featuring a check valve because it will prevent drainage when the system is shut off. In water systems, a check valve will prevent contaminated water from coming back into the main water supply.Best not to use
: A correct value has to be assigned for the cracking pressure which means the minimum pressure at which the valve will start functioning. If the value is not correctly estimated before installation and the real pressure is lower than expected, the valve will keep partially open, which will cause erosion of the parts. Also, check valves need to be installed at a fair distance from other fittings because this can cause them to function poorly or even block.
Control valves are often controlled by actuators and they are used to regulate variables such as pressure, level, flow or temperature based on a number of factors. A 3-way control valve
features 3 pipe connections which enables it to mix water from 2 pipes, to stop one entrance and open another or to split the flow coming from one pipe into 2 different pipes.Best usage
: Control valves are mostly used in industrial settings. Different parts of the system will send signals that will be picked up by sensors and transformed in commands for the valve. Here you can find 3-way control valves
Revit families ready for download.
How to work with valves in Revit
First, you need to have valve Revit families that you can place on your piping systems. Start by downloading this Valves Revit plugin
which will allow you to filter and search for the correct and most suited valve content you need. You can choose amongst several international manufacturers to make sure your content includes product information and is easy to order directly from the material list. You can also filter on different technical properties such as diameter, pressure stage or temperature range.
Once you find your perfect valve, select it and chose the pipe where you want to place it. The right fittings will be added to your system automatically without you having to set up every fitting for every valve you place. Watch this video to see the Valves Revit plugin
in action. Hope this article helped you and if you have any questions or are usually working with other types of valves and you want some more insight into those, drop us a line here.