Choosing Plastic or Brass Valves for your Lawn Irrigation System

People rarely pay attention to irrigation valves until something goes terribly wrong. Most Dallas homeowners would happily ignore them unless they suddenly spot that their sprinkler system is acting up. Unless they realize that they can’t stop water from flowing or shut off a zone, people rarely take any proactive steps to inspect the sprinkler system. The root cause of most of these troubles can be traced back to a harmless decision taken long ago: choosing a brass valve or plastic valve.

Both valves have their own set of pros and cons. We can’t simply describe brass valve as superior because there is no stat to prove the veracity of this claim. However, once the system starts aging, the difference between these two systems becomes apparent.

Why Valve Material Matters

Sprinkler valves are designed to withstand rough use. A typical sprinkler valve is designed to open and close over thousands of times in a given year without showing any sign of wear and tear. During peak seasons, each zone in a sprinkler system gets activated by a standard irrigation controller at least 100 to 150 times. In each cycle, these valves have to deal with issues like temperature shifts, vibrations and pressure fluctuations. These will definitely take a toll on the valves.

The selection of materials can have a serious impact on how these valves manage to operate under these extreme conditions. Valves made from plastics will definitely respond differently under stress than valves made from metal. We are not making any theoretical assumptions here, rather we are trying to draw a conclusion based on documented field performance. Valves, no matter what material it is made of, needs occasional replacement due to issues like internal wear and thread damage.

Plastic Valves

Most Plastic irrigation valves that we come across on a daily basis are either made from glass reinforced nylon blend or high-grade PVC. If they were made from poor-quality plastics, they will not last a month given the stress each valve has to go through each cycle. These PVC irrigation valves are designed to withstand regular wear and tear and can withstand water pressure up to 150 PSI.

The main advantage of plastic irrigation valve is that they are inherently resistant to corrosion. Plastic irrigation valve can easily deal with hard water and does not cause any pit or scale which is a common problem with brass valve. Internal parts of plastic irrigation valves in most cases stay smooth which is a big plus.

Another major advantage of plastic irrigation valves is that they are easy to install. You are less likely to deal with threading errors. The material has a bit of give which makes plastic irrigation valve an ideal choice for homeowners.

The biggest disadvantage of plastic irrigation valves is that they get badly damaged by the UV rays of the sun. Freezing can cause havoc on plastic irrigation valves if water somehow gets trapped. Expansion of water can cause the valve to develop cracks in such a situation. Also, we need to be careful while tightening these plastic irrigation valves as they tend to deform if they are overtightened.

Brass Valves

Brass valves give a solid feel which is hard to ignore. You will feel more confident with these brass valves as they are designed to last longer. Brass is known for its ability to withstand extreme water pressure, manage mechanical stress and tolerate temperature swings more effectively than its plastic counterparts. Therefore, it is no wonder that brass has been the top choice for plumbing over the last few decades.

Brass valves are also quite common in commercial irrigation settings. The rigidity of brass can easily tolerate frequent cycling and high flow rates without showing any signs of stress in the process. During the installation process, brass threads are also known for keeping their shape intact which is a big plus. Brass can well tolerate heat. That means, you can use these brass valves in shallow installs or in exposed valve boxes without a second thought. Compared to other metals, brass contracts and expands more predictably and this is what helps in preventing microleaks over the course of time.

However, the biggest downside of brass valves is that they can develop corrosion. Dezincification is a common problem faced by most components made from brass and therefore there is almost nothing we can do to stop it. Sudden system failure can be caused by this dezincification.

Pressure and Flow

40 and 80 PSI is the ideal range where residential irrigation systems tend to operate. You can use either plastic or brass valves as both materials are rated safe within this range. However, when you look at the flow volume, the difference becomes apparent. Internal turbulence is quite common when the flow rate is above 20 to 30 gallons per minute. Brass valves are designed to withstand such flow rate; however, plastic valves mainly rely on internal ribbing and wall thickness to withstand this immense pressure resulting from high flow. Under high-flow cycle, metal valves can maintain calibration to a certain extent whereas most plastic valves will capitulate under pressure.

Installation Errors and How Each Material Responds

There is no such thing as perfection when it comes to irrigation system installation. No matter how much you try, dirt and debris can get inside the line and sometimes, in worse cases, threads can also get tampered. Plastic valves

Known for their forgiving nature, plastic valves allow for minor installation mistakes. The threads of these plastic valves can flex a little without developing any cracks along the way. But when it comes to brass valves, they are not that forgiving. Permanent damage is sometimes unavoidable if you are doing cross-threading it. However, brass valves can easily undergo several rounds of servicing without developing any signs of stress, but plastic threads tend to deform or wear down with frequent and repeated disassembly.

Making the Choice

Most residential lawns are well suited for plastic valves. Water quality is also a decisive factor here. If the water is too harsh, maybe you should avoid using a brass valve but if you wish to do DIY maintenance every now and then, maybe it is a good idea to opt for a plastic valve. Brass valves are designed to withstand frequent maintenance cycles and higher flow.