Terms starting with F

Symbol for specified compressive strength, the design strength the engineer requires, usually at 28 days.

FF and FL, the paired numbers that measure how flat and how level a concrete floor is.

An F-shaped steel bar that hooks over handwheel spokes to give extra turning leverage on a valve. Shop talk

Contractor and installer word for any geotextile, as in road fabric, filter fabric or putting the fabric down. Shop talk

To fabricate something by cobbling it together from scrap and whatever is lying around. Shop talk

A disk-shaped gear with teeth cut on its flat face, meshing with an ordinary spur or helical pinion.

A rating factor that raises calculated stress to cover uneven load distribution across the face width.

Input variable deliberately set at chosen levels in an experiment, such as temperature, pressure, time or supplier.

Experiment that runs every combination of the chosen factor levels, so each main effect and interaction can be estimated.

Describes a valve that springs shut when it loses air, power or its control signal.

Describes a valve whose actuator drives it fully open when air, power or signal is lost.

A tidal current flowing in the same direction a vessel wants to go, adding to its speed over the ground. Shop talk

Dents in bearing races caused by vibration while the machine sits still, not by impact.

A small terminal unit with a fan, a filter and a water coil that heats or cools one room or zone.

Short connections that bring each pin of a dense part out to a via so it can be routed on other layers.

The tendency of charged powder to avoid inside corners and recesses because the electric field bunches on nearby edges.

Describes mix carrying too much binder: shiny, slick and prone to bleeding or rutting. Shop talk

Data entry error from a mistyped number, such as a slipped decimal or swapped digits, that shows up as a false signal. Shop talk

Cracking that grows a little with every load cycle until a bolt breaks far below its static strength.

Interconnected cracks in the wheel paths caused by repeated bending under traffic, known as alligator cracking.

Abnormally high current that flows when insulation fails and a short circuit or earth fault forms.

Fusion-bonded epoxy: a powder coating fused onto heated pipe, the standard external line pipe coating.

Fusion-bonded epoxy, a fast-curing epoxy powder applied to preheated pipe, rebar and valves for corrosion protection.

Flux-cored arc welding: arc welding with a tubular wire filled with flux, with or without shielding gas.

To taper new asphalt down to nearly zero thickness to tie it into an existing surface. Shop talk

To grind the start, stop or tack of a weld to a thin taper so the next bead can tie in smoothly. Shop talk

The ability of a survey system to find seabed objects of a stated minimum size, usually given as a cube edge length.

The CNC button that stops axis motion instantly while the spindle keeps running.

The fluidized container that holds powder and supplies it to the gun pumps.

The spindle speed and feed rate chosen for a cut, set from material, tool and machine.

The raw coating material fed into a thermal spray gun, as powder, wire, rod, cord or liquid suspension.

Sealed fitting that carries electricity, motion, fluid or light through a vacuum wall without leaking.

The water pumped into a steam boiler to replace the water boiled off, a blend of condensate and treated makeup.

Endless fabric that carries the wet sheet through the press nips and absorbs the water squeezed out of it.

Face of the sheet that was away from the forming wire, also called the top side.

Clipped form of femtosecond, for lasers and pulses lasting from a few to a few hundred quadrillionths of a second. Shop talk

The soft, low-carbon, body-centered cubic phase of iron that makes up most of an annealed low-carbon steel.

The precision ceramic or metal cylinder in a connector that holds the fiber and lines it up with its mate.

Package in which narrow nonwoven strip is folded back and forth into a box instead of being wound on a roll.

Quick repair of a furnace hearth and banks between heats by throwing or gunning in dolomite or magnesia. Shop talk

A periodic index pattern written into a fiber core that reflects a narrow band of wavelengths and passes the rest.

The fixed sequence of twelve colors that identifies each fiber and buffer tube in a cable.

A glowing damage wave that runs back up a fiber toward the laser, leaving a trail of bubbles in the core.

A clip-on tester that detects light in a fiber through a gentle bend, without cutting it or interrupting traffic.

A laser whose gain medium is an optical fiber with a rare-earth-doped core, pumped by diodes.

Paper or wood fibers torn out and stuck to the adhesive when a bond is pulled apart, showing the bond beat the substrate.

Small bare copper target on a board or panel that machine vision uses to locate it precisely.

A test that cuts a tab of cured sealant from an installed joint and pulls it to see whether it lets go of the substrate.

The angle across a light's beam at which intensity falls to 10 percent of its peak, marking the usable edge of the light.

Coating applied on site over the bare girth weld zone left between factory-coated pipe joints.

To lay pulled cable on the ground in a figure 8 pattern so it can be fed onward without twisting or kinking. Shop talk

A fiber of effectively unlimited length, extruded and laid down without cutting, as in spunbond webs.

Hard enough that a sharp file skates across the surface without biting, roughly 58 HRC and up. Shop talk

Fine mineral powder added to papermaking stock to raise opacity, brightness and smoothness and to cut cost.

The rod, wire, strip or electrode metal melted into a joint to build up a weld or braze.

The bead of adhesive left around the edge of a joint, which smooths stress at the ends of the bond.

A triangular sealant bead run into an inside corner where two surfaces meet at an angle.

Weld with a triangular profile laid in the corner where two members meet, the usual weld on T, lap and corner joints.

A thin sheet of partly reacted epoxy on a carrier, laid into joints and cured with heat and pressure.

The thickness of the cured coating, usually given in mils or microns.

A canister of desiccant in the refrigerant line that traps moisture, acid and debris.

Letting water pass across a geotextile while holding back the soil particles it carries.

The dust-sized part of the aggregate passing the No. 200 sieve, which stiffens the binder into a mastic.

Fiber fragments and small particles that pass a fine screen and have an outsized effect on sheet optics.

The smallest particles in a powder, roughly under 10 microns, which fluidize, charge and recycle poorly.

Smallest particle fraction of a refractory mix, which fills the gaps between coarse grains and forms the bond.

Powder particles smaller than the specified size range, which cause buildup, spitting and poor flow.

The sharpness of an optical cavity's resonances: free spectral range divided by the resonance linewidth.

Shop check of dragging a fingernail across a tooth flank to judge whether surface damage has real depth. Shop talk

The rough floor check of cure: dig a thumbnail into a cooled part and see if it marks. Shop talk

Skin oil and salt left on a vacuum-side surface by a bare hand, which outgasses for weeks and spoils base pressure. Shop talk

Describes a valve built to limit leakage through and around it during and after an external fire.

Alumina-silica clay refractory, the classic firebrick, graded from low duty to super duty.

The traditional title for a boiler operator who tends fires, watches water and keeps steam up. Shop talk

The surfaces of a boiler exposed to flame and combustion gases, as opposed to the waterside surfaces in contact with water.

A boiler in which hot combustion gases run through tubes that are surrounded by the water being heated.

The first good part off a new setup or program, fully inspected before the rest of the run is made.

Small round crater in wet paint where the coating pulls away from a spot of oil or silicone contamination. Shop talk

Long flat steel or fiberglass tape on a reel, pushed through conduit or walls to pull wire back.

Analysis that tests many variables or subsets in search of any significant result, almost guaranteeing a false positive. Shop talk

Wrinkle or bulge in the top sheet of a seam overlap that stops the two sheets lying flat for welding. Shop talk

A saddle-shaped cut on the end of a branch pipe so it sits flush against the curve of a larger pipe. Shop talk

An open wrinkle at the edge of a membrane lap that forms a channel water can run into. Shop talk

One of the successive physical barriers that keep radioactive fission products away from people and the environment.

Failures in time: one failure per billion device-hours, the standard unit for semiconductor failure rates.

Positioning and holding parts for welding with the right gaps, alignment and clean bevels.

A fast two-part epoxy that gels in about five minutes, the bench-repair go-to for quick fixes. Shop talk

Shop name for a spray washer with five tanks: clean, rinse, conversion coat, rinse and final seal or DI rinse. Shop talk

A measured position of the survey vessel at a recorded instant, and the act of determining it.

The time until a bond is strong enough to handle or unclamp the assembly without moving the parts.

The design and use of fixtures that locate and clamp parts the same way every time.

Indicator on a protection relay showing which element or phase operated; also the verb for it showing. Shop talk

A black fabric panel on a frame used on film sets to block light from hitting part of a scene or the lens. Shop talk

The end of a tape or label lifting off a curved surface and standing up like a small flag.

A sheet of burning gas across a furnace door that keeps air out while the door is open.

Surface hardening with an oxy-fuel torch followed by a water quench, used on large or one-off parts.

The control that runs a burner's start sequence, watches the flame, and shuts the fuel off fast if the flame fails.

The sensor that proves to the burner control that a flame is actually present.

The simplest thermal spray process: powder or wire melted in an oxy-fuel flame and blown onto the part.

A burner flame going out unexpectedly while the boiler is running. Shop talk

Either sloping side face of a screw thread, the surface that actually carries load between bolt and nut.

Wry crew slang for busy concert-style lighting full of strobes, chases and fast moving-light effects. Shop talk

Liquid refrigerant that turns to vapor because its pressure dropped, either at the metering device or where it shouldn't.

Lowest temperature at which an oil gives off enough vapor to ignite briefly when a flame passes over it.

Thin, quick layer of rust that forms on freshly blasted or water-washed steel within minutes to hours.

A thin orange rust bloom that forms within minutes on wet, freshly cleaned steel.

A thin rust bloom that forms on freshly blasted steel when it sits in humid air before coating.

The brief spike in surface temperature where teeth slide over each other under load, used to predict scuffing.

A safety device on an oxyfuel torch or regulator that stops flame from burning back into hoses and cylinders.

Liquid partly turning to vapor through a valve because downstream pressure stays below its vapor pressure.

Thin sheet metal or membrane installed at joints and interruptions in a wall or roof to direct water back outside.

Disruptive discharge over or around insulation that creates a short circuit through the air.

Describes sheet made by spinning a hot, pressurized polymer solution so the solvent flashes off and leaves a web of fibrils.

A countersunk screw head that sits flush in a cone-shaped seat, 82 degrees for inch screws and 90 for metric.

A flat area worn into a wheel tread when the wheel slides along the rail without turning. Shop talk

A stretch of water level data stuck at one value, a sign of a frozen, failed or dry sensor. Shop talk

Slang for a hot particle, a tiny speck of highly radioactive material found on clothing or skin. Shop talk

European name for an unbonded or lightly bonded fiber web or batt, from the German word Vlies.

The bending strength of plain concrete, measured by breaking an unreinforced beam and used for pavement design.

Rapid, repeated variation in light output over time, whether directly visible or not.

A spurious sounding that sticks out shoaler or deeper than the real seabed, usually from noise or a false detection. Shop talk

Describes an RTK solution whose carrier-phase ambiguities are not yet fixed, giving only decimetre-level accuracy. Shop talk

The finishing step that levels, compacts and opens the surface of a slab once the bleed water is gone.

A ball valve whose ball is held only by the seats and is pushed downstream by line pressure to make the seal.

Clump of entangled fibers in stock or in the finished sheet, the building block of poor formation.

Tidal current running in from the sea and up rivers and estuaries, mostly while the water is rising.

Damming a membrane area and filling it with water for a day or more to prove it does not leak.

Liquid refrigerant returning continuously to the compressor through the suction line while the system runs.

How far and how smoothly melted powder spreads out before it gels, which sets surface smoothness.

The relationship between how far a valve is open and how much flow it passes.

Running a low flow of dry nitrogen through copper lines while brazing to keep oxide scale from forming inside. Shop talk

The hot exhaust that leaves the boiler after combustion, made up mostly of nitrogen, carbon dioxide, water vapor and leftover oxygen.

Pulse energy per unit area, usually in J/cm squared, the quantity that sets ablation and optical damage.

A soft, fluid mud layer over the firm seabed that gives different depths at different sonar frequencies. Shop talk

Bleached softwood pulp made to be shredded dry into a soft, bulky fiber mass for absorbent cores and airlaid.

A liquid waterproofing applied by roller, squeegee or spray that cures into a continuous rubbery film with no laps.

A tank of powder kept airborne by air blown up through a porous floor, used to dip preheated parts.

Light a sample emits after absorbing UV, measured in paper as the gap between UV-included and UV-excluded readings.

Describes wipes and similar products designed to break up and pass safely through toilets, drains and sewers.

Material that shields molten metal from air and cleans oxides, as rod coating, wire core, granules or paste.

Loose airborne fibers released by opening, carding and cutting that settle on machines and floors. Shop talk

Fine powder captured from coal-fired power plant exhaust, used to replace part of the cement in concrete.

Single wild data point far from the rest, often a measurement or entry error rather than a real process change. Shop talk

Controlling a towfish's height above the seabed by adjusting cable length and boat speed. Shop talk

Ferritic nitrocarburizing: adding nitrogen and carbon below the critical temperature for a thin, hard layer.

Double-sided tape with a foam core, used to mount and bond parts with gaps, vibration or thermal movement.

A railfan, especially an excited one, as seen by the railroaders who work the trains. Shop talk

A stable layer of bubbles on the boiler water surface that makes level hard to read and carries water out with the steam.

The scheduled crew session in which the lighting designer directs electricians to aim and shape every fixture. Shop talk

Mist that forms inside a chamber during a fast pump-down when expanding air cools and its water condenses. Shop talk

A powerful, manually aimed spotlight that an operator keeps on a moving performer throughout a scene.

The North American working unit of light on a surface: one lumen falling evenly on each square foot.

Pattern of copper pads, outline and markings on a board that matches one component package.

The shape of the deposit a gun leaves in a short stationary shot or single line, used to check spray alignment. Shop talk

Field term for another operator's pipeline or buried metal structure near or crossing your own. Shop talk

Pipe that connects the exhaust of a high vacuum or booster pump to its backing pump.

A ratio of diurnal to semidiurnal constituent amplitudes used to classify a tide as semidiurnal, mixed or diurnal.

How evenly fibers are spread through a paper sheet, judged by small-scale variation in mass.

The temporary molds, supports and bracing that hold fresh concrete in shape until it can carry itself.

A tidal current running against a vessel's intended direction, slowing its progress over the ground. Shop talk

Four-ball test that raises load in ten-second steps until the balls weld, rating extreme pressure capacity.

Bench test that spins one steel ball against three clamped balls in a lubricant and measures the wear scars.

Square steel box 4-11/16 inches on a side, the step up from a four-square when #10 wire or big receptacles fill it. Shop talk

Shop name for an independent four-jaw lathe chuck, each jaw adjusted separately to center or offset work. Shop talk

A laser whose lower laser level sits above the ground state and empties quickly, so inversion is easy to reach.

Pair of offsets in one stick that carries conduit up over a wide obstruction, along it and back down.

Square steel box, 4 inches on a side, that takes a mud ring or cover and serves as the workhorse junction and device box.

The rule of thumb that measurement uncertainty should be no more than a quarter of the tolerance being checked. Shop talk

Paper machine design in which stock drains on a single, horizontal moving wire to form the sheet.

Flame-retardant glass-epoxy laminate grade that is the default base material for rigid circuit boards.

Federal Railroad Administration: the federal agency that sets and enforces railroad safety rules.

Experiment that runs a chosen fraction of all factor combinations, trading some aliased effects for far fewer runs.

Charged air molecules from a corona electrode that never attach to powder but still land on the part.

Ladle that starts teeming the moment the slide gate opens, with no oxygen lancing needed. Shop talk

The frequency spacing between neighboring resonances of a laser cavity, etalon or interferometer.

A soft-edged spotlight with a stepped Fresnel lens whose beam can be adjusted from spot to flood.

A long-handled steel trowel finishers swing across a slab from its edge to smooth it without walking on it. Shop talk

Wear from tiny oscillating slips between clamped parts, leaving reddish-brown oxide debris.

Lab slang for a laser diode, optic, coating or detector that has been destroyed by too much light or current. Shop talk

The count-rate meter and probe kept at exits for checking hands, feet and clothing for contamination. Shop talk

Slowly scanning a person or object with a contamination probe to find radioactive material before it leaves an area.

The crossing piece in a turnout or diamond where one rail passes through another and wheels cross the gap.

Shop word for the dull, frosted gray patches on gear teeth that turn out to be micropitting. Shop talk

Shop name for the dull, satin-gray sheen of early micropitting on gear teeth or bearing races. Shop talk

Film tear bond: a seam coupon that breaks in the sheet beside the weld rather than through the weld itself.

Fourier transform infrared spectroscopy, an oil test that fingerprints oxidation, contamination and additive loss.

Fiber to the Home: access networks that run fiber all the way into each residence.

Small unintended leaks of process gas or vapor to atmosphere, mostly from valve stem seals and joints.

The part of a boiler where the fuel actually burns, such as the big flame tube of a firetube or the water-walled box of a watertube.

The recipe of pulps, fillers, dyes and chemicals that make up a paper grade's stock.

Describes powder made by melting material into an ingot, then crushing and screening it to size.

A permanent joint made by melting two cleaved fiber ends together with an electric arc.

The instrument that aligns two fiber ends, welds them with an electric arc and estimates the splice loss.

Geomembrane seam made by melting the facing surfaces of two overlapped sheets and pressing them together.

Shop word for the fine metallic paste that collects on a magnetic drain plug from normal gear wear. Shop talk

Loose fiber ends on the surface of a nonwoven that lift into pills or lint when rubbed. Shop talk