In the Know


The Glossary is a list of industry-specific terms and acronyms commonly found in Symmons materials, such as catalogs, product documentation, social media, websites, and more.

Industry Terminology


ActivSense® is a line of high-quality, highly responsive sensor-activated lavatory faucets and soap dispensers from Symmons. ActivSense products are ADA-compliant and use an advanced sensor technology that virtually eliminates failed activation.

ActivSense faucets are available as single supply (for use with a point-of-use thermostatic mixing valve, such as the MaxLine® 8210CK) or as a dual supply with an integrated mixer handle.

There are three unique power options for ActivSense: battery (standard), AC adapter, or hard-wired multi-unit transformer. ActivSense faucets and soap dispensers can be ordered with an optional remote control to adjust settings, such as dosage and duration.

ActivSense faucets and soap dispensers are available in four distinct styles—Dia®, Duro®, Origins®, and Sereno®—and a variety of four finishes—Chrome, Brushed Bronze, Matte Black, and Satin Nickel—to blend with any décor.

All ActivSense products carry the Symmons 10-Year Commercial Warranty.


The Americans with Disabilities Act, or ADA, is a civil rights law that prohibits discrimination against individuals with disabilities in all areas of public life, including jobs, schools, transportation, and all public and private places that are open to the general public. The purpose of the law is to make sure that people with disabilities have the same rights and opportunities as everyone else. (Source:

Regarding plumbing fixtures, ADA compliance is a standard, not a certification. Local municipalities generally dictate what they believe is considered ADA Compliant.

There are many factors to consider for ADA-compliant design. The major requirements of federal legislation are:

– One-hand operation that does not require grasping or rotation
– Must not exceed 5 pounds of force to operate
– Hand shower must contain a non-positive shutoff


The American National Standards Institute (ANSI) is a not-for-profit, non-government organization that oversees the creation and use of voluntary health and safety standards for products and businesses across nearly all sectors of the U.S. economy.


A flowing back or reversal of the normal direction of water or wastewater from homes and buildings, leading to the possible contamination of potable water systems. Also see Cross Connection.

Backflow Prevention Device

Any valve, check valve, or mechanical device designed to automatically prevent backflow.


Building Management System. A Building Management System is used to monitor the plumbing, heating, and air conditioning mechanical systems in larger institutional, multifamily, hospitality, or other large commercial buildings.


An ancient alloy, composed primarily of copper (Cu) and zinc (Zn), used in the manufacture of faucets and other plumbing fittings. Small amounts of other alloying materials are also added for various types of brass to address the requirements of specific applications. Brass is also the term for a faucet finish, also known as polished brass.


Bronze is an alloy consisting primarily of copper (Cu), commonly with about 12–12.5% tin and often with the addition of other metals (including aluminum, manganese, nickel, or zinc) and sometimes non-metals, such as phosphorus, or metalloids such as arsenic or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as strength, ductility, or machinability.

Buy American Act

The Buy American Act requires Federal agencies to procure domestic materials and products. Two conditions must be present for the Buy American Act to apply:

– The procurement must be intended for public use within the United States; and

– The items to be procured or the materials from which they are manufactured must be present in the United States in sufficient and reasonably available commercial quantities of a satisfactory quality.

All Symmons products that meet compliance for the Buy American Act include a reference in their supporting documentation. Products can also be filtered by checking the “Buy American Act” box under Special Attributes filter section on the Product Search page.

Centerset Faucet

A centerset faucet is a popular bathroom lavatory faucet that is typically constructed with the deck plate, spout, and handles as one unit. This type of faucet requires three holes in the mounting surface (countertop or sink).

The three holes are 4 inches apart at the widest point (4 inches from the center of the hot water supply to the center of the cold water supply) with a hole in the middle centered at 2 inches. This faucet configuration is easy to install and is very popular for nearly every installation situation.


One of the basic elements (Cu), copper is used for plumbing piping, and is one of the alloys used to make brass, a key material in the manufacture of faucets and fittings.


CPVC is the abbreviation for chlorinated polyvinyl chloride, a high-temperature plastic pressure piping system designed for drinking (potable) water plumbing systems. CPVC can be used for water temperatures up to 200° Fahrenheit. CPVC is produced by adding chlorine to PVC during the manufacturing process to make it safe for drinking water.

CPVC pipe is joined to CPVC fittings by means of a two-step primer (cleaner) and solvent glue, which has a different chemical compound than standard PVC primer and glue, so it’s important to use the proper glue when installing CPVC piping. CPVC pipe is available in nominal sizes from 1/2″ to 24″ and is approved in all model plumbing and mechanical codes across the United States and Canada.


A cross-connection in a plumbing water system is bad situation. Typically, a cross-connection is a situation where the drinking water supply (referred to as potable water) is allowed to mix with a non-potable supply. When this unsafe water enters the drinking water system through a cross-connection, there is a risk of injury or illness due to contaminants such as bacteria, chemicals, or other dangerous pollutants.

Adherence to plumbing codes helps to reduce the chances of cross-connections and crossovers, as codes require certain fittings and piping designs to prevent scenarios where cross-connections could happen. Examples of devices that prevent cross-connections and crossovers are backflow preventers, check valves, and vacuum breakers.


Crossover, or cross-flow, is a type of cross-connection that occurs when hot water and cold water are unknowingly mixed, or allowed to mix, within the plumbing system.

For example, if a garden hose is connected to the hot and cold water lines with a Y connection, and the supplies are left turned ON but the garden hose sprayer is OFF, water from one side will migrate into the line with the lower pressure. This situation could result in hot water in the cold water line, or vice versa.

Adherence to plumbing codes helps to reduce the chances of cross-connections and crossovers, as codes require certain fittings and piping designs to prevent scenarios where cross-connections could happen. Examples of devices that prevent cross-connections and crossovers are backflow preventers, check valves, and vacuum breakers.

Design Specification

A Design Specification (also known as a Design Spec or Full Specification), clearly identifies each item and the required criteria related to that item. Regarding plumbing products, a Design Spec defines necessary attributes like finish color, product material, number of handles, and compliance requirements, among other specifics.

Diverter Spout

A diverter spout is a tub spout that includes a manually activated gate to divert the water from the tub spout to the showerhead or another outlet, such as a hand shower.


An escutcheon is the plumbing term for a faceplate or trim ring for a shower valve, diverter valve, or any other type of decorative cover for a valve or piping trim ring.

Evolution® by Symmons

Evolution® is an agile, scalable building management system that uses non-invasive wireless sensors to identify water and HVAC issues and detect leaks. Evolution can sense water data points, such as temperature and humidity fluctuations, water flow, water usage, and active external leaks.

The data gathered by Evolution’s sensors is communicated through a dedicated wireless LoRa® gateway that is included in the Evolution package. This time-tracked data is then displayed on the Evolution Dashboard and the Evolution smartphone/mobile app. Alerting can be configured so that staff members can be notified when a temperature, humidity, flow, or usage threshold is crossed, or when an active external leak is detected.


A device designed to control and guide the flow of water. Examples include faucets, showerheads, shutoff valves, shower valves, and drinking fountain spouts. Some people call these “fixtures,” but that term means something different to the plumbing industry.

The differing usage of “fitting vs. fixtures” can lead to unintended consequences, such as when legislation calls for changes in fixtures, although the true intent involves changes in fittings.


A device for receiving water and/or waste matter that directs these substances into a sanitary drainage system. Examples include toilets, sinks, bathtubs, shower receptors, and water closet bowls. The term is used erroneously in common vernacular to describe fittings.


GPM is an abbreviation for Gallons Per Minute. Also known as flow rate, GPM is a measurement of how many gallons of water flow from a fixture within a one-minute span.

Hand Shower

A hand shower is a handheld showerhead or wand controlled by a shower valve and connected to the piping by means of a flexible hose. It can be mounted on a bracket in place of the showerhead, or it can be an additional spray option that’s mounted separately on the wall with a fixed bracket or attached to a sliding bracket on a bar.

Hand showers are particularly beneficial for people with disabilities or mobility issues. All hand showers should be equipped with a check valve and a non-positive shutoff to prevent a cross-connection in case the shower valve is left in the On position and the hand shower is shut off.

Hand Spray

A hand spray is a spray option for a kitchen faucet. The spray typically includes a short hose that either pulls out of the faucet itself or from a separate mounting ring in the sink. The flexible hose enables the sprayer nozzle to reach all areas of the sink, or to rinse food items such as vegetables. It may also be referred to as a vegetable sprayer.

Hex Key Wrench

A hex key wrench, also commonly referred to as an Allen wrench, is a hexagonal-shaped tool used to install, tighten, and remove fasteners with a recessed hexagonal-shaped head. Hex key wrenches are commonly used on plumbing products to tighten and remove hex key set screws on handles and hardware, among other applications.


HydroMersion Technology is a proprietary fluid engineering design developed by Symmons to channel low, code-regulated flow rates into best-in-class force and functionality, doing more with less. The first line of products to use this new technology are the HydroMersion showerheads and hand showers, which will be available in May of 2024.


While sometimes used by the general public to mean a bathroom or washroom, the plumbing industry uses lavatory to mean a bathroom washbowl or basin permanently installed with running water. The plumbing industry uses the term “sink” in reference to kitchen or other types of sinks, such as janitor’s sinks and hand sinks.


When referring to aspects of plumbing systems, leaching refers to the process of dissolving a soluble component out of a constituent material at a wetted surface. Materials commonly leached into drinking water from water distribution systems, known as leachates, include copper, lead, and nickel.


One of the basic elements (Pb), lead is a soft metal that has been used in plumbing systems for thousands of years. The word “plumbing” derives from the Latin word for lead, plumbum. Lead has a unique ability to resist pinhole leaks, while being soft enough to form into shapes that deliver water most efficiently. Its softness and malleability were for a long time highly desirable properties for manufacturing everything from pipe to paint. Lead is a neurotoxin that can accumulate in the body in soft tissues, as well as bone.

Lead and Copper Rule (LCR)

A United States Environmental Protection Agency regulation dating back to 1991, LCR requires water systems to monitor drinking water that comes through faucets in homes and buildings. If lead concentrations exceed 15 parts per billion (ppb) or copper concentrations exceed 1.3 parts per million (ppm) in more than 10% of homes and businesses sampled in a regional plumbing system, the system must take actions to control corrosion and leaching.

If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health, including the possible replacement of plumbing system piping.


Under section 1417(d) of the Safe Drinking Water Act, “lead free” is defined as being no more than 0.2 percent of materials used in solders, and no more than 8 percent of materials used to manufacture pipe, fittings, and well pumps.


Leadership in Energy and Environmental Design (LEED) is a green building certification program used worldwide. Developed by the non-profit U.S. Green Building Council (USGBC), it includes a set of rating systems for the design, construction, operation, and maintenance of green buildings, homes, and neighborhoods, which aims to help building owners and operators be environmentally responsible and use resources efficiently.

Buildings can qualify for four levels of certification:

Certified: 40–49 points
Silver: 50–59 points
Gold: 60–79 points
Platinum: 80 points and above


In the plumbing industry, low-flow fixtures and fittings refer to plumbing products that meet the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term “low consumption.”


LoRa (short for Long Range) is a spread spectrum modulation technique derived from chirp spread spectrum (CSS) technology. LoRa is a long range, low power wireless platform used as a wireless platform of Internet of Things (IoT).

While Wi-Fi is used to connect billions of personal and professional devices in homes, LoRaWAN is used for home security and access control, leak detection, and fuel tank monitoring, and many other applications.

LoRa® – LoRa® is a trademark of Semtech Corporation.


The MaxLine® TMV is the line of proprietary point-of-use thermostatic mixing valves from Symmons for commercial tempered water applications. All MaxLine valves are machined from solid semi-red brass and stainless steel and are covered by the Symmons 10-Year Commercial Warranty.

In 2021, Symmons upgraded its popular 3/8″ compression TMV as the 8210CK to meet strict new national code requirements for lower flow rates, with reliable performance down to as low as 0.35 GPM.

Non-Positive Shutoff (NPSO)

A non-positive shutoff, or NPSO, is a single-action valve (off/on) that partially shuts off the water flow off to a device. The closure significantly reduces the flow yet allows a trickle of water to pass by to prevent backpressure in the main valve that could lead to crossflow (hot water migrating into the cold water side of the plumbing system, or vice versa).

An example of a non-positive shutoff on a Symmons product would be the button or lever on a hand shower wand in a shower that is controlled by a Temptrol shower valve. If the water is turned on at the shower valve but then the flow is shut off with the non-positive shutoff on the shower wand, a minimal trickle of water will continue to flow from the wand.

The purpose of this trickle is two-fold; first, it eliminates the chance of any backpressure that could cause crossflow. Second, the trickle of water acts as an indicator to remind to the user that the water supply is still turned on and should be shut off at the main device when complete.


Founded in 1944, NSF International is a not-for-profit, non-governmental organization that develops standards and product certifications in the area of public health and safety.

NSF/ANSI Standard 61

A standard related to products that come in contact with drinking water. Developed by NSF and conforming to the ANSI voluntary standard, the standard was accepted by the NSF board in 1988 to confirm that such products will not contribute excessive levels of contaminants into drinking water.

Most U.S. states and many Canadian provinces require products used in municipal water distribution systems and building plumbing systems to comply with Standard 61.

Performance Specification

A Performance Specification is criteria determined by the designer, architect, or engineer for the contractor to prepare and deliver a package of work within a set of parameters. This specification enables the contractor to propose cost-effective solutions to achieve a final package that satisfies the design intent drawings.


PEX piping or cross-linked polyethylene is a type of flexible piping that has been gaining popularity recently. As an alternative to copper and galvanized piping, PEX synthetic piping is a favorite among DIYers and in new construction projects.

PEX piping systems use barbed fittings that insert into the PEX tubing, and then a metal ring is crimped over the piping and the fitting, making a watertight seal. The advantages of PEX systems are fast install, flexible tubing, less fittings, and no flame required.

PEX Cold Expansion

PEX Cold Expansion, sometimes referred to as PEX-A, is flexible, cross-linked polyethylene that is very similar to standard PEX tubing, yet it uses plastic rings to secure the fitting, rather than the metal crimp rings used on standard PEX tubing.

These plastic rings are expanded with either a hand tool or a power tool, then slipped over the PEX joint. These expanded plastic rings will quickly contract to their normal size, thereby making a watertight seal on the barbed fitting.


A not-for-profit trade association of plumbing products manufacturers. PMI member companies produce most of the nation’s plumbing products.

Potable Water

Water that is satisfactory for drinking, culinary, and domestic purposes.

Pressure-Balancing Valve

Also known as a pressure-compensating valve, this device is designed to reduce the risk of thermal shock and scalding while showering. Required by code in most areas of the United States, a pressure-balancing valve balances the hot and cold water pressures coming in from the supply line and compensates for variations to maintain the water temperature. Such variations can occur when a toilet is flushed or a washing machine started while someone is showering.


ProPress® is a method of joining copper pipe developed by Viega®, LLC. As opposed to the traditional method of joining copper pipes by heating the joints with a torch and applying solder, ProPress copper fittings feature a type of rubber sealing element inside, and the fitting is pressed or crimped onto the copper pipe with a power tool.

The major advantage of ProPress fittings over soldered fittings are the ability to work with water in the piping; fittings cannot be soldered with water in the piping because the water cools the surface and disrupts the full flow of solder within the fitting joint. Other advantages include fast install and no flame required.

PVD Finish

PVD stands for Physical Vapor Deposition. This process, which occurs in a vacuum chamber, electrostatically applies extremely thin, but extremely dense coatings of exotic metal alloys onto fittings. The resulting finish is state-of-the-art in durability, scratch-resistance, and lasting beauty for faucets. A wide range of finishes with PVD is possible, including chrome, nickel, brass, and bronze.


ReadyStock is one of the three stocking categories in the Symmons Stocking Program. ReadyStock items are always in stock, and they ship within three days, regardless of quantity, guaranteed. ReadyStock always has thousands of our most popular products in stock and ready to go!

Safe Drinking Water Act (SDWA)

The Safe Drinking Water Act (SDWA) is a federal law originally passed by Congress in 1974 to protect public health by regulating the nation’s public drinking water supply. Amendments were passed in 1986 and in 1996. The SDWA requires many actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and ground water wells. SDWA authorizes the United States Environmental Protection Agency to set national health-based standards for drinking water to protect against both naturally occurring and man-made contaminants. Enforcement is accomplished through the National Primary Drinking Water Regulations.

Semi-Red Brass

Semi-Red Brass is a high-quality brass alloy that contains more copper and less zinc than inferior yellow brass. Symmons chooses to use high-grade semi-red brass because it resists dezincification, a process in which the zinc elements in inferior brass products begin to break down and lead to cracking and leaking. Semi-red brass is also heavily utilized in the making of marine hardware due to its corrosion-resistance qualities.

Special Order

Special Order is one of the three stocking categories in the Symmons Stocking Program. Special Order products are generally unique or low-volume products that are built to order for projects with extended lead times of 18 weeks or more. Minimum order quantities may apply.

If you need customized products, our Design Studio™ can make your ideas a reality.

Standard Product

Standard Product is one of the three stocking categories in the Symmons Stocking Program. Standard Product is defined as product that’s regularly in stock, and will ship in three days. It’s recommended that customers call for availability of large orders of 10 items or more. The Standard Product stocking category includes a wide variety of showers, faucets, valves, parts, and accessories.


Temptrol is a proprietary pressure-balancing shower valve engineered and released by Symmons in 1968. Temptrol shower valves use the pressure-balancing design originally invented by Paul Symmons in Boston, Massachusetts in 1939.

This pressure-balancing concept prevents the scalding or freezing known as “shower shock” when someone is showering and then a large volume or rapid amount of water is run in another part of the building, such as flushing a toilet.

Temptrol valves can be ordered with many combinations of configurations, piping connections, mounting brackets, shower systems, or finish trim kits. All Temptrol valves are constructed of semi-red brass, bronze, and stainless steel, and they are proudly cast, machined, assembled, and packaged in the USA.

Thermal Shock

A large and sudden change in water temperature. Thermal shock is a particular concern for showers when there is a rapid change in water temperature due to reduced pressure in the hot or cold water supply, sometimes referred to as “shower shock.”

The most common example is when someone flushes a toilet while another person is showering. Thermal shock can lead to scalding, as well as increased risk of injuries due to slips and falls when there is a surge of cold water.

Symmons invented the concept of pressure-balancing shower valves in 1939, specifically to eliminate thermal shock from shower valves when the pressure dropped in either the hot or cold supply line. The world’s first shower valve to feature pressure-balancing technology was the Symmons SafetyMix®, and that same pressure-balancing design was integrated into the Symmons Temptrol® valve when it was released in 1968.

The SafetyMix and the Temptrol continue to be the industry leader in pressure-balancing shower valves.

Thermostatic Mixing Valve (TMV)

A thermostatic mixing valve (TMV) is a valve that senses the temperature of the water to adjust the mix of hot and cold water to prevent scalding. This type of valve maintains a safe, comfortable water temperature whether the fluctuation is due to a change in the pressure or the temperature of the incoming hot and cold water supplies.


In the plumbing industry, ultra-low flow fixtures and fittings refer to plumbing products that exceed the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term “high efficiency.”


A fitting with a movable part that opens or closes one or more passages and thereby allows a liquid flow to be started, stopped, and regulated. In plumbing, valves are used in faucets and showers, and can be called mixing valves because they control the mix of hot and cold water to achieve desired water temperatures.


An internal flow diverter within Temptrol shower valves made from 2019 onward that enables the user to switch between any two functions without the need for a secondary diverter valve. Showers with VersaFlex valves can be used for any two combinations of showerhead, hand shower, or tub spout.

Volume Control

The Volume Control lever found on Symmons shower valves is a simple device that lets the user control the amount of water that flows from the valve to the showerhead, depending on their preference.


WaterSense is a partnership program sponsored by United States Environmental Protection Agency, which works to promote water efficiency and enhance the market for water-efficient products, programs, and practices.

Similar to the EnergyStar program that helps consumers choose energy-efficient appliances, WaterSense helps consumers to choose water-efficient products by specifying the maximum flow rates and minimum performance levels. Products certified as meeting current WaterSense product specifications are eligible to carry the WaterSense label.

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