Glossary of Terms

Glossary. Keyboard

Actuator

A device that opens or closes a valve, either manually or automatically.

Advanced Groove System (AGS)

A complete system of Victaulic products offering a proprietary wedge-shaped groove profile for the strongest and most dependable mechanical pipe joining system for 14-78″/DN350-DN1950 pipe. The only system available to feature two housings up to 60” in size.

Air (Circulating)

Air distributed to habitable spaces for heating, cooling, or ventilation.**

Air Conditioning

Controlling/changing the temperature, humidity, purity, and flow of a building’s air (environment).

Air Handling Unit (AHU)

Key mechanical equipment in PHA systems that moves air from the building space, through filters and over a chilled water coil, to clean and condition the air.

Air Separation Unit

A device used to remove air from the system fluid. Air reduces the efficiency in PHA systems and can unduly wear equipment and components.

Air Terminal Unit

A device that distributes, controls, and sometimes conditions air into a zone or space. Often is a variable air volume (VAV) box. Typically contains a variable speed fan, controlled damper, and a hot and/or cold water or electric resistance coil.

Air Valves

Automatic air release valves allow the release of air bubbles from pressurised pipes. Combination air valves release bubbles from pressurised pipes while providing for large volume release during pipeline filling and vacuum break. Victaulic in partnership with Bermad, offers various hydraulic control valves in particular US and Canadian markets.

Annular Corrugations

Circumferential, ring-shaped indentations in pipe.

Atmospheric Pressure

Pressure of the outdoor environment. Approximately 14.7 psi | 101.4 kPa | 1 bar at sea level and varies inversely with elevation.

Authority Having Jurisdiction (AHJ)

*An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.

AWWA

American Water Works Association

Backflow

Reverse flow in a water system from the normal or intended direction. This includes flow around pumps and mechanical equipment, where it can create inefficiency in the system and undue wear of equipment.

Backflow Preventer

A device designed to prevent reverse flow in a water system. Can be used as another term for a check valve. Also the common term for a combination of two adjacent check valves, that prevent backflow of closed-loop system water from getting back into the public water supply and causing contamination.

Baffle

A surface, usually in the form of a plate or wall, used in cooling towers to disperse the warmer water and encourage heat release into the atmosphere.

Balanced Heat Recovery

Occurs when internal heat gain equals recovered heat and no external heat is introduced to the conditioned space. Maintaining balance may require raising the temperature of recovered heat. Many, if not most, systems do not have balanced heat recovery over time (e.g., during unoccupied periods or extreme cold) and require supplemental heat to overcome heat losses.**

Bellows

A flexible rubber component, traditionally used around mechanical equipment and pumps for vibration attenuation. Although flexible, it is not recommended for accommodating significant pipe deflection or misalignment. Must be replaced periodically due to wear.

BIM

Building Information Modelling; The process of designing a building collaboratively using one coherent system of computer models.

Blind Flange

A round, flat, solid flange used to cap off system ends. Must be tapped with a pressure release valve for safety concerns.

Blowdown

The common practice of attaching a small ball valve to a tapped port on a strainer access cap, and opening it periodically to “blowdown” and purge debris from the basket, without opening the cap. This is not as effective as proper periodic removal and cleaning of the basket.

Boiler

A vessel in which water is heated, not necessarily to its boiling point, and used for heating purposes.

Boiler Feedwater

Water supplied to a boiler.

Bolted Split Sleeve

Coupling style that wraps around the pipe and provides a leak-proof joint while allowing for some flexibility at the joint. Available restrained or non-restrained.

Booster Pump

A pump used to increase the output of the primary pumps in a system, or to supplement the water supply pressure as in a typical potable water (plumbing) system in a high-rise building.

Boundary Layer

The region of a fluid flowing through a pipe contacting the pipe wall. This is where friction between the fluid and the pipe wall takes place, causing frictional head losses in a piping system.

Branch Line

The pipes supplying sprinklers, either directly or through sprigs, drops, return bends, or arm-overs.

Braze

Joins metals by the melting of non-ferrous alloys (filler metal) that have melting points above 800°F | 425°C, but lower than those of the metals being joined. This is typically done by using a brazing acetylene torch.

Break-Even Temperature

The outdoor temperature at which total heat losses from conditioned spaces, equal internally generated heat gains.**

British Thermal Unit (BTU)

A heat energy measurement unit. One BTU is the heat energy required to raise the temperature of a pound of water from 59°F to 60°F | 15°C to 16°C.

Bushing

Secondary bearing for the piston rod on a valve that is pneumatic or hydraulically actuated. Also called a “drive nut” on a manual valve.

Butt Weld

A weld formed by placing two pieces of material parallel to one another (“butted” together). Typically the preferred method for welding large diameter pipe.

Butterfly Valve

A valve consisting of a pair of semicircular plates that are attached to a spindle across a pipe and hinged to allow flow only one way.

Capacity

Load for which an apparatus is rated (electrical generator or thermal system) at specific conditions.**

Cavitation

The formation of vapor pockets (cavities) in a liquid. Cavitation is a phase transition between the liquid and the vapor condition. The vapor pockets can cause excessive rapid wear of pump impellers, as well as noise. Suction diffusers, and proper system design and pump selection, can prevent this condition.

Centrifugal Pump

Devices that provides the primary force, to distribute and recirculate hot and chilled water, in a variety of space-conditioning and plumbing systems. The pump provides a pre-determined flow of water to the space load terminal units, or to a thermal storage chamber for release at peak loads. Other hydronic systems that use pumps include (1) condensing water circuits to cooling towers, (2) water-source heat pumps, (3) boiler feeds, and (4) condensate returns. Centrifugal pumps can also be found in water treatment and service water heating systems.**

Changeover Temperature

The outdoor temperature the designer selects, as the point of changeover from cooling to heating by the HVAC system.**

Chiller

A key piece of mechanical equipment in chilled water systems. Removes heat from the chilled water loop and transfers it to the condenser water loop (if water cooled), or directly to the outside air (if air cooled). Consists of a compressor, condenser, and evaporator (cooler). Chillers are defined by the way that they transfer the heat between the loops (compressor or chemically) and their size (measured in tons of cooling). Absorption chillers use a chemical and thermal reaction to transfer heat. The more common chillers use mechanical compressors to transfer the heat with pressurized refrigerant. Centrifugal, scroll, and screw chillers are the common types of mechanical compressor chillers.

Clean Agent

*Electrically non-conducting, volatile, or gaseous fire extinguishing that does not leave a residue upon evaporation.

Clean Out Plug

Allows particles to be cleaned out of the bottom of the valve during maintenance/seat cartridge replacement.

Closed Loop Water System

A system that is not open to the atmosphere. These systems experience little or no corrosion, because new (aerated) water is not being continuously introduced to encourage oxidation. They are initially charged with water and then isolated.

Code

*A standard that is an extensive compilation of provisions covering broad subject matter, or that is suitable for adoption into law independently of other codes and standards.

Coefficient Of Performance (COP)

The ratio of beneficial heat, transferred at the heating and/or cooling heat exchangers of a heat pump, to the energy used to power the heat pump. If both heating and cooling heat transfer are beneficial, both can be considered, though this is usually denoted as a combined COP.**

Coil

A cooling or heating element made of pipe or tube that is used to encourage heat transfer to (cooling) or from (heating) the fluid, to the air passing over/through it. Coils can be very large as with a centralized air handling unit (AHU) cooling coil, or much smaller in a localized terminal unit (VAV) coil.

Commissioning

The process of starting-up, verifying, and documenting the performance of buildings and systems to meet the owner’s specified requirements. This can also include training operations personnel on long-term operation and maintenance of systems.

Compliance

Meeting the requirements of a governing code and/or standard.

Compressor

The mechanism of a chiller that compresses refrigerant to increase its temperature and pressure, thereby enabling heat transfer in the condenser of an air conditioning system. Also refers to a piece of equipment that compresses air for use with pneumatic tools or controls.

Computer Aided Design (CAD)

A computer software system in which engineering designs are created. Can be in two-dimensional (2D) or three-dimensional (3D) versions.

Condensate

Water created from cooling steam in boiler systems. In chilled water systems, the water created on the cold coil from the air, as part of the dehumidification process.

Condensation

Moisture that forms on exposed metallic piping and equipment that is cooler than the surrounding air. This is not desirable as it can lead to corrosion, safety hazards, or property damage. Typically, chilled water applications require piping to be insulated with a vapor barrier to prevent this condition.

Condenser

A heat exchanger in which refrigerant is condensed from a high-pressure high-temperature gas to a liquid, by rejecting heat to the condenser loop water. The condenser water then carries that heat to the cooling tower, where it is rejected to the environment. Thus, the cool refrigerant condenses back to the liquid state, and drains from the condenser to continue in the refrigeration cycle.

Construction Drawings

The working drawings a contractor uses to actually construct a project. They include specific detail confirmed directly on-site.

Cooling Tower

Heat transfer equipment that utilizes evaporation, to transfer heat from condenser water to the outside atmosphere. Water is diffused (by spraying or running over plates / baffles) to induce evaporation. Air can be forced through the unit (convection) to further encourage evaporation, even at temperatures significantly higher than that of the fluid. There are many different designs, but all utilize basically the same theory. Closed cooling towers are not directly open to the atmosphere, and behave similarly to a typical heat exchanger.

Cooling Tower Cell

Smallest cooling tower subdivision (unit), which can function as an independent heat exchanger. Multi-cell cooling towers are common on larger projects.**

Corrugated

Annular or helical indentations in pipe for the purpose of adding flexibility.

Coupling

A coupling is a device used to connect or join pipe, fittings, valves, accessories and equipment. Victaulic invented the grooved mechanical coupling in 1919.

Damper

Varies the volume of air passing through a terminal unit or duct.

Decibel

A unit of noise/vibration amplitude (volume, loudness).

Deluge Sprinkler System

*A sprinkler system employing open sprinklers that are attached to a piping system that is connected to a water supply through a valve that is opened by the operation of a detection system installed in the same areas as the sprinklers. When this valve opens, water flows into the piping system and discharges from all sprinklers attached thereto.

Demand (Load)

The required heating or cooling load, based upon all contributing factors (e.g. people, structure, outside temperature, inside temperature, insulation factor of structure, etc.).

Design-Build

A construction contract for which the scope includes full design and construction services. Also called an Engineer, Procure, and Construct (EPC) or turn-key contract.

Detail Drawings

Drawings that provide a closer, more detailed look at specific elements of a design.

Dielectric Coupling

A component that provides an electrical current isolation and physical separation of dissimilar metal components or pipes, to prevent galvanic corrosion.

Differential Pressure

The difference in pressure readings between two points in a system. Can be interpreted to a flow rate across special orifices like venturis, diffusers, and valves.

Diffuser

A fitting incorporating baffles, louvers, or other means of directing (diffusing) air flow from a duct. Most often located on the ceiling or walls.

Distribution Piping

A system of pipes, valves, and fittings that carries water from the mechanical equipment, to the terminal units throughout the building or from the valve room to the sprinkler systems throughout the building.

District Cooling And Heating

Cooling and heating systems that utilize a central plant to heat and cool a campus of buildings (e.g. offices, manufacturing, schools, etc.). The central utility plant houses all of the major mechanical equipment. Large distribution piping systems carry the cooling and heating water throughout the complex or campus.

Domestic Water

The term used for public or potable water plumbing systems.

Dry Pipe Sprinkler System

*A sprinkler system employing automatic sprinklers that are attached to a piping system containing air or nitrogen under pressure, the release of which (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve, and the water then flows into the piping system and out the opened sprinklers.

Dry Sprinkler

A sprinkler secured in an extension nipple that has a seal at the inlet end to prevent water from entering the nipple until the sprinkler operates. Following the release of the first flexible dry sprinkler by Victaulic in 2016, the extension nipple referred to in the NFPA Glossary is no longer assumed to be rigid.

Elastomer

An engineered, synthetic, elastic polymer or rubber.

Elevation Drawings

Drawings that provide a two-dimensional (2D) “side-view” of a project section or element.

Evaporation

The process of liquid water turning to vapor. This is the key principal behind hydronic cooling systems. The evaporation process is a heat energy transfer process. Cooling towers are a perfect example of this process.

Evaporator

The component of a chiller that exchanges heat from the chilled water loop to the refrigerant. Evaporating refrigerant removes heat from the chilled water and lowers its temperature.

Expansion Joint

A joint that makes allowance for thermal expansion of the parts joined without distortion.

Expansion Tank

A partially filled vessel (tank) on the top (highest elevation) of a hydronic heating system, that allows volume expansion of the water due to heating without damaging the system components.

Fan Coil Unit

Consists of a fan and a hot and/or cold water coil, to add or remove heat to the air that is drawn over the coil.

Fiberglass Reinforced Plastic (FRP)

A composite material made of a polymer matrix, reinforced with fiber. It is used in a lot of different applications, including the manufacturing of air ducts.

FireLock NXT™ Devices

Fire Protection Valves for Dry, Deluge and Preaction systems, with a consistent valve body design through all applications. Industry-first to eliminate air-to-water differential, which eliminates field calculations and set-up time. Vic-Quick Riser trim configuration was the first in the market to offer a fully trimmed valve, drain connection kit, preset air supervisory and alarm switches, control valve, and Style 009N Installation-Ready™ Couplings for quick placement into service.

Flange Adapter

A device that provides a direct connection between a flanged component and a component with a different end connection (such as a groove).

Flange

A rim that can be welded or screwed onto the end of a fitting or pipe. The flanges of the mating pipes and fittings are joined together with bolts. Most flanges require gaskets between them to prevent leaking.

Flat Face (FF) Flange

A flange that is flat across the entire face. This flange uses a gasket that has bolt holes cut in it and that covers the entire flange face.

Flexible Coupling

A pipe joint that is designed to accommodate axial pipe movement at the joint. It allows for controlled linear and angular movement, which accommodates pipeline deflection as well as thermal expansion and contraction.

Flexible Drop

A flexible connection between the branch line of the sprinkler system, and the sprinkler itself.

Flow Velocity

Directional speed of water in pipes, measured in feet/meters per second.

Flux

Acidic pastes used in brazing/soldering to prepare pipe ends and fittings, and prevent the formation of oxides that can inhibit proper leak-free joining.

Friction Loss

The loss of energy in a flowing fluid, attributed to the amount of drag created by the surface it is flowing on or against. In terms of piping, it is the amount of friction generated by both the material, surface finish and interior surface area of the pipe itself, and the resultant loss of fluid velocity.

Frictional Resistance

Resistance to fluid flow, due to friction between the fluid and the contact surface across which it flows.

Gate

A metal obstruction lowered into the valve, used to stop and start flow.

Gate Connector

Attaches the gate to the actuator. Contains a slot that the seat cartridge slides into.

Gauge Pressure

Pressure above that of atmospheric pressure. This is the pressure shown on a system pressure gauge.

Guides

Provide lateral pipe restraint, but allow movement of pipe along its axis for expansion, etc.

Header

A horizontal pipe, from which smaller diameter pipes (drops) branch downwards to pumps and other mechanical equipment.

Heat Exchanger

Mechanical equipment that transfers heat from one fluid loop to another. The fluids are not mixed, but physically separate. Shell and tube are the most common types. Plate and frame heat exchangers are also common in PHA systems. Heat exchangers are often used for low cost heat exchange in lieu of chillers, when conditions and loads are favorable.

Helical Corrugations

Spiral or corkscrew style indentations in pipe.

High-Density Polyethylene (HDPE)

Fastest growing segment of pipe in the world; presents a cost-effective solution for a variety of markets including water and wastewater, industrial, mining, oil and gas, and power; applications include potable water, wastewater, slurry, gas, and oil. HDPE pipe is flexible, durable and resistant to breakage due to freezing.

Hybrid Emitter

A Victaulic-patented device designed to atomize water to <10μm and distribute both nitrogen and <10μm water particles into a hazard area.

Hybrid Fire Extinguishing System

A fire extinguishing system capable of delivering hybrid media at the specified design rate and proportion.

Hybrid Media

Water mist and inert gas agent combined in a controlled proportion, where both components are contributing factors in fire extinguishment.

Hydraulic Control Valve

Valves used to control variables such as pressure, flow or level that can be configured to provide given functions without external power. Configurations include On/Off, Pressure Reducing, Pressure Relief, Pressure Sustaining, Surge Control, Level Control, Pump Control, Flow and Burst Control. Victaulic in partnership with Bermad, offers various hydraulic control valves in particular US and Canadian markets.

Hydronics

The use of water, or similar heat-transferring fluids, to transfer heat energy in a heating or cooling system.

Hydrostatic Pressure

The force exerted on an interior pipe area by water.

Innovative Groove System (IGS)

A proprietary groove profile, specifically designed and optimized for 1″ | DN25, schedule 10 to schedule 40, carbon steel pipe. Featuring a shorter “A” dimension than that of the OGS groove profile, it enables a shorter take-out dimension compared to current OGS solutions. The groove profile supports the Victaulic® FireLock™ IGS line of products, and is cold formed in the field without removing any metal from the pipe wall by the RG2100 roll grooving tool. The pipe wall thickness at the bottom of the groove is larger than the pipe wall thickness at the bottom of the first exposed thread on pipe schedules down to 10. Using smaller pipe schedules allows for increased flow, optimising system pressure.

Inspection Services

Victaulic offers Inspection services, sending a Victaulic inspector to your jobsite to verify proper installation and place a guarantee on the pipe installation for the life of the system.

Insulation

Material used to prevent condensation and subsequent corrosion on cooling system piping, and to retain heat and prevent human contact (burns) on heating system piping.

Intelligent Roll Groover

Innovative roll grooving tool that utilizes laser sensors, position sensors, and touch screen operation to provide instant feedback on the quality of the grooved pipe end

Isometric Drawings

Drawings that provide a three-dimensional (3D) line drawing.

Kelvin

A unit of temperature measurement. 1° Kelvin = -272.15°C = -457.87°F.

K-Factor

The flow coefficient of a fire sprinkler.

Knife Seal

Prevents media from leaking out of the top of the valve, around the kife. Also scrapes the slurry off of the knife as it is opening.

Koil-Kit™ Coil Packages

Victaulic KOIL-KIT(TM) Coil Packs provide a simplified, quality coil circuit installation while ensuring optimal hydronic system design requirements are met. They are suitable for a variety of hot and cold water application.

Laminar Flow

A smooth uniform flow condition. Provides greatest efficiency, but only occurs in sufficiently long straight pipe runs. Direction changes, fittings, valves, etc., cause turbulence in piping.

Load Factor

A percentage that describes the average demand on a system, divided by the maximum possible demand on that system, over a certain time period. In terms of PHA systems, it assists in describing how much a particular system is being utilized, compared to what it is capable of producing.

Main

The horizontal pipes that carry water from the riser to the individual branches.

Mechanical Drawing

A graphical representation of mechanical, plumbing, and other mechanical and fire protection systems, equipment, and components. Drawings contain critical notes and details regarding the specific project requirements.

Mechanical Room

The area of a facility or building that houses the key mechanical equipment including chillers, boilers, pumps, etc.

Mechanical Properties

The physical properties of materials including tensile strength, yield strength, etc.

Micron

A unit of measure. 1 µ = 0.00003970 inches. For reference a standard automatic sprinkler system discharges drops of water that are 1000+ µ in diameter, while a Victaulic Vortex(TM) hybrid emitter discharges drops of water that are < 10 µ in diameter. White blood cells and naturally occurring fog are two types of media with similar diameters of ~10 µ.

Noise and Vibration Attenuation

Victaulic couplings dampen noise and vibration through the unique construction of our grooved couplings. They enable the gasket to seal against pipe, while the housing provides both space for the seal to flex and containment to prevent overstretching. They create a permanent leak-tight seal. Additionally, ductile iron absorbs sound.

Open Loop System

A water system that is open to the atmosphere in some part of the process. This continuously introduces oxygen into the fluid and can cause corrosion. Condenser water systems with open cooling towers are a good example of an open loop system. Plumbing systems are also considered open loop.

Outside Stem & Yoke (OS&Y) Valve

*An indicating valve that has components that show if the valve is open or closed.

Packing

Material packed around a valve stem to prevent leakage.

Packaged Air Conditioner (DX)

A complete air conditioning unit including a refrigeration compressor, cooling coils, fans, filter, automatic controls, etc. assembled into one unit. No piping is necessary; the air is directly cooled and set to the building.

Packing Gland

Used to compress the knife seal against the gate.

Penthouse Mechanical Room

A mechanical room located on the top level of a building, as opposed to a basement level.

PHA

Plumbing, heating and air conditioning.

Pilot-Operated And Actuated Valve

A control valve that uses a pilot to control the flow of water into an actuator, that regulates the open and closing positions of the valve based upon the set point of the pilot and the system pressure. This type of control valve can be used for pressure reducing, pressure control, and pressure relief.

Pilot-Operated Diaphragm Valve

A control valve that uses a pilot to control the flow of water into a diaphragm chamber, that regulates the open and closing positions of the valve based upon the set point of the pilot and the system pressure. This type of control valve can be used for pressure reducing, pressure control, and pressure relief.

Pilot Valve

A small valve that controls a limited flow control feed to a separate, primary valve.

Plan Drawings

Drawings that provide a two-dimensional (2D) “looking down” or “from above” view of a project section or element.

Plenum

**A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.

Pneumatic

Containing or operated by air or gas under pressure.

Preaction Sprinkler System

*A sprinkler system employing automatic sprinklers that are attached to a piping system that contains air that might or might not be under pressure, with a supplemental detection system installed in the same areas as the sprinklers.

Preliminary Drawings

Drawings used to provide general arrangement and system layout for information purposes only. They are not typically accurate or detailed enough for actual construction or even bidding.

Pressure

The force exerted per unit area. Usually expressed in pounds per square inch (psi) or kilopascals (kPa).

Pressure Control Valve

*A pilot-operated pressure reducing valve, designed for the purpose of reducing the downstream water pressure to a specific value under both flowing (residual) and non-flowing (static) conditions.

Pressure Drop

Pressure differential, often used to indicate flow velocity across a valve or orifice.

Pressure Reducing Valve

*A valve designed for the purpose of reducing the downstream water pressure under both flowing (residual) and non-flowing (static) conditions.

Pressure Regulating Device

*A device designed for the purpose of reducing, regulating, controlling, or restricting water pressure.

Pressure Relief Valve

*A device that allows the diversion of liquid to limit excess pressure in a system.

Raised Face (RF) Flange

A flange with a wide raised rim around the center. This flange uses a wide flat ring gasket that is squeezed tightly between the flanges. The facing is machine-finished with tiny spiral grooves that bite into and help hold the gasket.

Refrigerant

Synthetic fluid used in heat transfer processes, in conjunction with some types of compressors. Varying pressure and temperature of refrigerants increases the effectiveness of absorbing or rejecting heat.

Retaining Plate

Keeps the seat in the housing during operation

Retrofit

Modifications made to existing equipment and systems. Retrofit projects provide unique installation challenges because of the existing environment, and potential safety and logistic issues in occupied buildings.

Rigid Coupling

Does not allow for movement, similar to a flanged or welded joint.

Riser

A vertical pipe that supplies each main from the water source.

Schedule

Pipe wall thickness is expressed in “schedules.”

Seat

The material that a valve disc seals against.

Set Point

*A predetermined value to which a device or system is adjusted and at which it performs its intended function.

Shop (Fabrication) Drawings

Drawings that provide details on specific sections of the piping, with precise dimensions necessary for proper prefabrication of spools.

Sight Glass

A transparent tube or window, through which the level of liquid in a reservoir or supply line can be checked visually.

Slip-On Flange

A flange that slips over the end of a pipe, and is welded to the pipe both at the neck and at the face of the flange.

Socket Weld

A weld formed by inserting a pipe end into the socket (recessed area) of a fitting. Commonly used in small diameter applications.

Soffit

An architectural feature or structure often used to conceal piping.

Soldering

The process of joining copper pipe / tube by applying heat lower than 800°F | 450°C, and applying a filler metal to join and seal the joint. Also known as sweating.

Solenoid Valve

A valve that is actuated electromechanically. A plunger, which is controlled by an electromagnetic coil, opens and closes an orifice that allows the valve to open or maintain a closed position.

Sound Attenuation

The reduction of noise transmitted through piping and structures. Mechanical equipment like pumps generate significant vibration and noise that must be diminished, to prevent transmission to a building’s occupants.

Specification

An engineering design document that defines the specific details of all project equipment, systems, components, and construction methods.

Sprinkler System

*A system that consists of an integrated network of piping designed in accordance with fire protection engineering standards that includes a water supply source, a water control valve, a waterflow alarm, and a drain and is commonly activated by heat from a fire, discharging water over the fire area.

Sprig

*A pipe that rises vertically and supplies a single sprinkler.

Standpipe

*The system piping that delivers the water supply for hose connections, and for sprinklers on combined systems, vertically from floor to floor.

Stroke Limiter

Limits the distance the gate can travel out of the valve during normal operation. This is specific to the Series 795, and is not found on competitive knife gate valves

Support

A device used to hold the weight of piping. Can be specially designed to allow movement or attenuate vibration. Hangers are supports suspended from above the pipe.

Sweating

Condensation on cold piping. Also another term for soldering of copper joints.

Tack Weld

A weld that holds parts of an assembly in proper alignment until the finish welds are made.

Throttling

Controlling flow velocity with a valve that is neither completely open (100%), nor completely closed (0%). This differs slightly from balancing, which is typically a more precise control utilizing globe valves.

Ton Of Cooling

The time rate of cooling equal to 12,000 BTU / hour (approximately 3517 watts). The energy to maintain a one ton block of ice for one hour.

Trip

To actuate or open.

Tube

Unlike pipe, tube is designated by its outside diameter and wall thickness, which is often described in terms of “gauge” number. Certain tubes maintain a constant inside diameter, and the outside diameter changes with wall thickness (but this is typically rare in commercial applications). Pipe is designated by a nominal outside diameter (OD) and wall thickness.

Turbulent Flow

Unstable erratic flow. A typical condition after abrupt direction changes or restrictions in flow. This condition can be undesirable at the suction end of a pump, therefore suction diffusers or straight pipe lengths are utilized to stabilize the flow. This can also be a desirable flow state in certain valve applications or processes that require mixing.

Two-Pipe System

A hydronic heating or cooling system that utilizes only one coil per terminal unit. This coil has one pipe in (supply) and one out (return) of the unit. Typically, these systems will have a central air handling unit (AHU) moving cool air to the terminal unit (VAV), and the internal coil of the unit will be for heating.

Vacuum

Any internal pressure (gauge) less than atmospheric pressure. Absolute vacuum is estimated at 14.5 psi | 100 kPa | 1 bar or 29.9″ | 101.3 kN / m.2 of mercury (Hg) on a manometer.

Valve

Diverts, stops, or controls flow. Used in PHA systems for isolation (shut-off) of equipment or systems and throttling (control) of flow. Common types include ball, butterfly, check, globe, gate, and plug valves.

Valve Trim

All internal and external wetted parts (stem, plug, disc, seat, etc.) of a valve. It is important to specify proper materials for valve trim to ensure chemical compatibility of materials.

Vapor Barrier

A method of sealing insulation in a chilled water system from the surrounding atmosphere, to prevent moisture from penetrating the insulation and causing condensation on the piping.

Variable Air Volume (VAV) Box

A terminal unit that controls air flow volume based upon demand. Typically contains a heating and/or cooling coil, a fan, and an electronically controlled damper.

Velocity (Flow)

The directional speed (feet/meters per second) that fluid moves through piping.

Venturi

A device used to measure flow velocity. A specially designed machined opening (orifice) causes a predictable pressure drop, for flow rates within a specific range. The pressure on either side of the orifice is measured and the difference calculated. A chart (or electronic device) is then used to interpret the flow rate.

Vic-BoltlessCoupling and Tool

A secure, tamper resistant, low profile joint that is installed only with Victaulic® Style 792 tool.

Victaulic Original Groove System (OGS)

Victaulic, originally known as The Victory Pipe Joint Company, designed and patented the first mechanical bolted coupling. The concept was groundbreaking: joining pipe with bolted mechanical grooved couplings, using a gasket seal. Since that time, the actual groove profile has continued as an area for deeper engineering exploration. Victaulic offers several distinctly different groove profiles intentionally designed to meet the needs of various system applications, most of which are proprietary technologies. But from the beginning there has only been one Victaulic Original Groove System profile, and that remains the global standard definition for the original groove profile.

Victaulic System Solution for Saturated Steam

The first mechanical pipe joining solution for steam and condensate piping; the system is comprised of couplings, a full line of fittings, and new roll sets designed for forming a new groove profile.

Visual Inspection
Water Hammer

A sudden intense stress condition in piping, caused by a pressure spike resulting from a sudden change in liquid velocity. Often caused by a sudden accidental closure of a valve during full flow. Tremendous forces can be generated and ultimately result in system component and support failures.

Water Mist System

*A distribution system connected to a water supply or water and atomizing media supplies that is equipped with one or more nozzles capable of delivering water mist intended to control, suppress, or extinguish fires and that has been demonstrated to meet the performance requirements of its listing and (the applicable) standard.

Water Supply

*A source of water that provides the flows [gal/min (L/min)] and pressures [psi (bar)] required by the water-based fire protection system.

Weld

The process of joining similar metals using a high-intensity electric arc at temperatures from 1500°F to 2000°F | 816°C to 1093°C. The arc melts and fuses the base metals. In most cases, a filler metal is melted along with the base metal in order to strengthen the joint. The finished joint is as strong as, or even stronger than, the base metals that have been joined.

Weld Neck Flange

A flange with a long tapered hub that is welded to the pipe end. The hub reinforces the flange, and allows material to flow smoothly between the pipe and the flange.

Wet Pipe Sprinkler System

*A sprinkler system employing automatic sprinklers attached to a piping system containing water and connected to a water supply so that water discharges immediately from sprinklers opened by heat from a fire.

X-Ray Testing

A non-destructive examination method that uses radiation (x-rays) to penetrate a weld and produce an image on film. This provides a permanent record of the weld quality. Also referred to as radiographic testing (RT).

Yoke

Frame that supports the valve actuator. Contains a location for lockout/ tagout pins.