Unit weight of the concrete in pcf and the full height of fresh concrete in the form in ft, which set the full-liquid-head capIn: Formwork, shoring, and reshoring
Mass of free water divided by mass of cementitious material; w/cm when supplementary cementitious materials are includedIn: Mix design and water-cement ratio
w/c (w/cm)
Mass of water divided by mass of cementitious material; the master variable for strength and permeabilityIn: Mix design and water-cement ratio
W/D or A/P ratio
Section factor, weight or area over heated perimeter, that drives the thickness; heavier members need lessIn: Structural fireproofing
Weight correction factor for three conductors in the conduit, often around 1.4 when they ride cradled in the bottom, and closer to 1.2 for a true triangular (trefoil) arrangementIn: Cable pull planning and tension card
WAGD
Waste anesthetic gas disposal, the system that scavenges exhaled anesthetic so it does not pool in the roomIn: Medical gas piping field guide
Wage determination (WD)
The official schedule of classifications and their base and fringe rates for a locality and construction typeIn: Certified payroll and prevailing wage
An insulated box, cooler or freezer, built from foamed panels with a sealed door and vapor barrier, cooled by a unit cooler fed from a remote condensing unitIn: Commercial refrigeration field guide
Walking body voltage
Peak voltage a person builds walking the floor in their footwear; commonly held under 100 V peak per STM97.2In: ESD floor testing field guide
The permanent steel box in the wall, standard 42 by 16 inches, that the chassis slides intoIn: PTAC and PTHP field guide
Wall tie
The corrosion-resistant anchor that ties a veneer back to its structural backupIn: Masonry construction
Wall tie / free-standing height
The engineered anchor tying the mast to the building, and the height the mast can stand before it needs the first tieIn: Mast-climbing work platform safety
Warm wall line
The inside face of the exterior wall, the line the eave ice barrier must extend pastIn: Ice dams and snow load
A warning-line-bounded zone on a low-slope roof where infrequent, temporary work is allowed away from the edge without conventional protectionIn: Rooftop permanent fall protection
Warping
Often used the same as curling; some references reserve it for the moisture-gradient edge liftIn: Slab curling and warping control
Money set aside against the warranty cost a job is expected to generate later, so the cost is matched to the job instead of surprising a future month. Also called a warranty accrual. Treatment is the CPA's.In: Warranty reserve and cost management guide
Warranty rider
A written manufacturer approval keeping the watertight warranty in force with the array installedIn: Solar-ready roof provisions
Wash-water containment / reclaim
Capturing the runoff with drain covers, berms, and a vacuum, then reusing or disposing of it legallyIn: Pressure and soft washing
Washboarding
Regular corrugations from traffic on a dry, loose, poorly bound surface; also called corrugationIn: Aggregate base and gravel roads
Washout
The contained area for cleanout slurry and waste prime, kept out of storm drains and off-site soilIn: Concrete pumping and placement
Washout test
Washing a fresh sample to recover and weigh the fibers, confirming the dose in the loadIn: Fiber-reinforced concrete
The cast hub built into a water closet carrier that the bowl discharges into and that connects to the branch or stackIn: Fixture carriers and supports guide
Waste heat recovery
Capturing the heat a data center would reject and putting it to use instead of dumping itIn: Data center waste heat reuse
Water balance / LSI
The Langelier Saturation Index from pH, temperature, alkalinity, calcium, CYA, and TDS; near 0 is balanced, high scales, low corrodesIn: Pool and spa mechanical systems
Water bond
A conductive surface in contact with the water, commonly at least 9 sq in, tied into the gridIn: Pool and spa bonding field guide
Water budget / seasonal adjust
A percentage that scales every zone's run time up or down by season; also a utility's annual gallon allocation for a siteIn: Smart irrigation field guide
Water closet
The plumbing trade name for a toilet, flushed by a gravity tank, a pressure-assist tank, or a flushometerIn: Fixtures and water efficiency
Water closet carrier
A floor-mounted carrier with the toilet's waste fitting built into the frame, the most common carrier on the jobIn: Fixture carriers and supports guide
Water delivery time
Time for water to reach the inspector's test connection, measured from when that connection is fully opened; commonly held to 60 seconds on qualifying systemsIn: Dry-pipe and pre-action trip test
A sealed device with a permanent air or gas charge that absorbs the surge, listed to ASSE 1010 / PDI WH-201In: Water hammer arrestor guide
Water mist
A system of very fine water droplets that cool and locally smother with far less water than a sprinkler, governed by NFPA 750In: Data center fire suppression compared
Drinking-water treatment makes raw water safe to consume; wastewater treatment cleans used water before discharge to the environmentIn: Treatment plant systems field guide
Weight of water to cementitious material, tight in pervious at roughly 0.27 to 0.34 per the mix designIn: Pervious concrete field guide
Water-powered backup
A backup that uses municipal water pressure through a venturi to pump the sump, no battery neededIn: Sump pump backup protection guide
Water-resistive barrier (WRB) / drainage plane
The lapped layer behind the siding, house wrap or felt, that drains water that gets past the cladding down and outIn: Siding installation
Waterfront permit
The federal, state, and local authorizations required to build in the water, including Army Corps and submerged-land approvalsIn: Boat dock and marina construction
Waterline tile / coping
The tile band set at the water level on the bond beam, and the coping cap on the pool edge that sheds water away and transitions to the deck across an expansion joint.In: Commercial pool construction
Waterlogged
A failed expansion tank whose bladder has ruptured, so water has filled the air side and there is no cushion leftIn: Thermal expansion tanks
Waterproofing
A treatment that resists water under hydrostatic pressure, typically a membraneIn: Below-grade waterproofing
Waterproofing / wall protection
The moisture barrier, air gap, drainage plane, and root barrier that keep constant water and roots off the building structureIn: Living wall and green wall systems
Waterproofing membrane / flood test
An ANSI A118.10 bonded sheet or liquid layer under tile in wet areas, proved by holding about 2 in of water in the pan for 24 hours before tiling.In: Ceramic and porcelain tile installation
A model of the hammer, pile, and soil that relates blow count and stress to capacity, run in GRLWEAPIn: Driven pile foundations
Waviness index
ASTM E1486 measure of mid-wavelength deviation, 2 to 10 ft, that affects rolling ride and FF does not senseIn: Floor flatness and levelness
Wax ring
The seal between a toilet outlet and the closet flange; a failure leaks gas and water at the baseIn: Sewer gas odor field guide
Wax ring / gasket
The seal between the toilet bowl horn and the closet flange, compressed when the bowl is set and bolted downIn: Fixture rough-in and setting guide
WBGT
Wet bulb globe temperature, which adds sun, wind, and radiant heat, the measure NIOSH and ACGIH use for occupational heatIn: Heat illness prevention
WBS
Work breakdown structure: the job split into the activities you schedule, broken by area and operationIn: Construction scheduling field guide
WCR
Withstand and closing rating, the short-circuit current the switch can survive and close into, per UL 1008In: ATS commissioning field guide
WDM
Wavelength-division multiplexing, carrying several signals on one fiber by using different colors of lightIn: Optical circuit switch and photonics
Weaning
Stretching the watering interval and widening the wetted zone over time so the tree learns to find water on its ownIn: Tree establishment and aftercare
The slotted intake in the aquifer that admits water and holds back sand, sized by slot to the formation or gravel packIn: Water well drilling and well systems
Air temperatures with and without evaporative cooling; together they give humidity and the load input for a superheat chartIn: HVAC test instruments field guide
Wet chemical
The potassium-based liquid agent that saponifies and cools a grease fire; the system type UL 300 requires for cooking hazardsIn: Hood suppression semi-annual guide
A sprinkler system charged with water at the heads, ready to flow on a fused head; the code baseline, avoided over live racksIn: Data center fire suppression compared
Tapping a main under pressure with a sleeve, valve, and tapping machine, cutting and retaining a coupon without taking the main out of serviceIn: Water service and meter tap guide
The tank that collects the incoming wastewater between pump cycles; its working volume is the storage between the pump-on and pump-off levelsIn: Sewage lift station field guide
An inline circulator whose motor rotor spins in the pumped water, cooling and lubricating the bearings with no mechanical seal to leakIn: Hydronic pump install field guide
WFT
Wet film thickness in mils, the coating depth right after application, before it curesIn: Roof coating mils and yield
WFT / DFT
Wet film thickness, the gauge reading right after application, and dry film thickness, the cured depth the warranty is written toIn: Roof coating mils and yield
While-in-use cover
A weatherproof receptacle cover, the bubble cover, that stays weatherproof with a cord plugged inIn: Temporary power field guide
Whip
The flexible conduit branch drop from the panel to a receptacle at the rackIn: PDU and RPP commissioning
Rod or cable X-bracing that resists lateral load in braced bays, and the short angle that holds a frame flange from bucklingIn: Metal building erection
Wind clip
A metal clip at the tile nose or side that resists uplift, standard in coastal and high-wind workIn: Tile roof installation
Wind load
The force and overturning moment the wind puts on the sign's exposed area, the load that controls structural designIn: Electric sign installation
Wind rider
An add-on extending coverage to wind damage up to a stated speed, such as 55, 72, or 110 mphIn: Roof warranty types and NDL
Shutting off, draining, and blowing out the water lines and protecting the trap so they do not freeze and split in a cold climateIn: Outdoor kitchen construction guide
A report of all open contracts showing contract value, costs, completion, earned revenue, and billingsIn: WIP report and over/under billing
WIP schedule
Work-in-progress report comparing cost incurred and percent complete to billings, job by job, to show over/underbilling and fadeIn: Construction cash flow and WIP
Wire mesh / basket tray
Welded mesh tray, light and field-formed, the standard for LV, data, and fiberIn: Cable tray field guide
Wire saw
Diamond-beaded wire for thick, massive, or odd-shaped cuts a blade cannot reachIn: Concrete cutting and coring
Wireway
A covered metal or nonmetallic trough used as a raceway for many conductors, NEC Article 376 or 378In: Wireway and gutter field guide
Fault current the bus and structure can take, with short-time gear rated to hold it for an interval such as 30 cyclesIn: Distribution equipment guide
Witness / signoff
The independent person who attests a test happened as recorded, and the signature that closes an item; the inspect, witness, and accept chainIn: Proof packet assembly
Witness mark
A brittle paint stripe across a torqued fastener and its body that shows it was torqued and cracks if it later movesIn: Termination torque QA field guide
Asphalt produced at a lower temperature using an additive or foaming processIn: Asphalt plant production
WOG / CWP
Water-oil-gas or cold working pressure, the maximum non-shock pressure at ambient temperatureIn: Plumbing valve types
Wood shake vs wood shingle
A shake is split, so it is thick, rough, and irregular; a shingle is sawn on both faces, so it is thinner, smooth, and uniformIn: Wood shake and shingle roofing
Wood-burning vs gas
Open wood fire with sparks and smoke, versus a controllable gas burner over rated mediaIn: Outdoor fire feature guide
The transponder a worker carries so a machine's antenna can detect them. RFID covers a broader range; ultra-wideband resolves position to the centimeter for tighter, tunable zones.In: Proximity warning and struck-by safety tech
Workforce development
Defining roles, training and certifying people, building hiring pipelines, transferring knowledge, and retaining the teamIn: Data center staffing and workforce
The distance from arc source to the worker's face and chest the incident energy is reported at; typically 18 to 36 in by gear typeIn: Arc flash study and labels
A fixed, recurring seven-day period the employer sets, the basis for the FLSA 40-hour overtime thresholdIn: Field time tracking and labor hours
World Athletics certification
Class 1 or Class 2 testing and measurement that qualifies a track for sanctioned competitionIn: Running track surfacing
Woven vs nonwoven
Woven is high strength and low flow for separation and reinforcement; nonwoven is high flow for filtration and drainage.In: Geotextile separation fabric
WPS
Welding procedure specification, the recipe bounding process, filler, preheat, interpass, and parametersIn: Weld heat input and CWI acceptance
The water-resistive barrier and the gap behind the cladding that drains water down and outIn: Stucco and EIFS
WSFU
Water supply fixture unit, a dimensionless load value for a fixture, folding flow, duration, and frequency of useIn: Water supply pipe sizing guide
WSP
Working steam pressure, the separate lower rating for saturated steamIn: Plumbing valve types
WUCOLS
Water Use Classification of Landscape Species, the UC reference rating plant water use from very low to high by regionIn: Xeriscape and drought-tolerant design
Water usage effectiveness and power usage effectiveness; the water-versus-energy scorecard for data-center coolingIn: Evaporative cooling and swamp coolers
Wye (star, Y)
A connection with a common neutral point; line-to-line voltage is 1.732 times line-to-neutral, line current equals phase currentIn: Three-phase wye vs delta