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Most popular types of valves and how to use them as Revit families

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.

Gate valve

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.

Globe valve

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

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.

Balancing valves

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 valve

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.

Check valve

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.

Best usage: 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 valve

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.

You Could Connect Elements in Revit 6x Faster than You Are Currently Doing It

09 August 2018

The old way of connecting families in Revit

Revit provides a few useful tools that enable you to automatically connect elements by means of fittings when designing piping systems. Here are just a few:

1. With the “Add Vertical” tool you are able to connect pipes using the current slope value.
2. If you want to disregard the slope value, you can use the “Change Slope” tool.
3. The “Automatically connect” placement tool lets you automatically connect to the snaps on a component when starting or ending a duct segment. This option is useful for connecting segments at different elevations.

What if your elements were previously designed or imported?

However, you sometimes have to connect elements that are already drawn. In order to do this, you have to create separate section views, carefully align and drag the connectors of your elements to the positions where they need to connect, and only after performing all of these preparing activities can you hit “Connect”. Sometimes, Revit even adds unwanted elements to your system that you have to later remove.

What can you do about this?

You can use a smart Revit plugin that lets you connect elements by simply selecting their corresponding connectors. Like this, you will avoid switching between section views to correctly align the pipes. The plugin will do this for you. Watch this video to see the difference between the design flows in Revit vs the Revit plugin.


Read further: Rotate Revit Families the Easy Way

Away with Gas, Welcome Heat Pumps. Which one is the Best?

08 August 2018

One subject that cannot be ignored these days is the debate concerning the shift from traditional fuel-based heating solutions to alternative and more environmentally safe methods such as boilers and heat pumps. This discussion fits in the larger context of the global concern to reduce energy consumption and utilize forms of renewable energy. As such, the Paris Agreement stands proof for the collective initiative undertaken by a lot of nations to set things in motion and essentially do everything in their power to prevent the global temperatures this century from rising with more than 2 degrees Celsius above pre-industrial levels. In the Netherlands for instance, this translates to a 95% reduction of CO2 by the year 2050. Quite an ambitious target.

What is your role as an MEP engineer or contractor in this?

As an MEP professional, you situate yourself at the foundation of this discussion and, together with other stakeholders such as project owners and architects, you represent the steering wheel that has the power to influence the project one way or the other.

When deciding about the energy source to be used for space heating and hot water systems, you usually have to take into account a number of factors such as the efficiency of the source, the environmental friendliness of the fuel, the installation and maintenance costs and the overall comfort they provide. How do you fill in your checklist? Read on and you’ll get the information you need to take a responsible decision.

Efficiency

COP - Coefficient of Performance

A genuine indicator of efficiency is the coefficient of performance (COP) that represents the ratio between the amount of heat or cooling produced and the amount of energy and resources required to generate that result. In the case of a gas heating system, every 1kW of gas energy burnt will result in 0.85kW of heat, which represents a COP of 0.85.

Heat pumps are essentially different since they don’t use only one resource or fuel as input. Heat pumps use electricity to transfer energy from heat sources recovered from the outdoor environment. So for every 1kW of electricity put in, the heat pump will produce up to 4kW of heat, which means a COP of 4. When calculating the COP, bear in mind that it is dependent on several conditions such as the size of the building, the insulation and temperature variations. In the case of lower outside temperatures, a heat pump will output less heat due to the fact that it simply takes less heat from outside.

Running costs

It is common amongst home and large project owners to think that the initial investment in a heat pump is not justified since it can be more expensive than a gas-fueled system. While this can be true in some cases (see “Installation and maintenance costs” section below), one needs to look at the long-term costs in order to correctly appreciate the efficiency of a heat pump. When taking into account the number of months and the average amount of hours per day that the heat pump is working, we will see that using heat pumps is indeed much cheaper on long-term than traditional gas heating systems. Use this handy running costs calculator to check your specific situation.

Installation and maintenance costs

2 in 1 system

Unlike a traditional heating method such as a gas furnace, a heat pump doesn’t have to generate heat itself. Instead, it uses electricity to transfer heat that already exists from one area to another. Heat pumps perform a double job: in summer they keep the temperatures cooler inside and in winter they deliver more heat. For homeowners, this means that they don’t have to install two systems – a furnace and an air conditioner – because a heat pump will do the job of both. Consequently, the costs of installation, maintenance, repair or replacing are reduced to nearly half. With regard to maintenance the following. Most units consist of two parts. For a heat pump based on external air input the outdoor unit will be more difficult to maintain than an indoor unit.

Investment

For a heat pump investment is needed compared to a mainstream central heating solution.
You can think of connecting the gas pipes from the control cabinet and an exhaust gas hose for the boiler. In the long run these will have to deliver a certain payback and return on investment based on the estimated consumption and potential savings.

Comfort

Safety

Traditional fuel based heating systems can pose serious dangers for several reasons. First, they display hot surfaces or flames within the easy reach for children or adults which can result in domestic injuries. Second, they pose the risk of carbon monoxide poisoning which can result in death. Heat pumps eliminate these risks and make for safer and more environmentally friendly heating methods.

Extended features

Heat pumps also present a number of modern advantages such as dehumidifying, air filtration, the even distribution of warm air around the house, remote wi-fi control, hour scheduling and temperature control, features that add value to the overall customer experience.

What is your responsibility?

Now is your time to act. You have the possibility to majorly contribute to the reduction of pollution around the world while delivering better, more sustainable and more convenient methods of heating. Take a look at the MEPcontent library of Revit families and AutoCAD files for heat pumps and download the ones you will use in your projects. Which one is the best? That is up to you to decide, depending on the project demands and your preferences. You can choose manufacturer specific content from Mitsubishi Electric, Nibe, Hisense, Fujitsu, Saunier Duval, Buderus, Viessmann and several other manufacturers. View the library now and select your favourite!