Glossary of Terms

AAR

Abbreviation for Association of American Railroads.

Ad Valorem Tax

A charge levied on persons or organizations based on the value of transaction. It is normally a given percentage of the price of the retail or manufacturing stage and is a common form of sales tax; e.g. Federal excise tax on new trucks and trailers

Adapter, Cam & Groove

The male portion of a quick coupling device for pipe or hose ends.

Adapter, APR

A spring loaded shut-off valve mounted on the tank trailer designed to mate with the terminal loading device. API RP 1004 specifies dimensions for these adapters.

Adapter, Openable Bottom Loading

A bottom loading adapter that is capable of being used to unload a product.

Aerator

A device for adding diffused air into the tank for the purpose of aiding the flow of dry product during unloading.

API

Abbreviation for American Petroleum Institute.

Appurtenance, Cargo Tank

See 49 CFR 178.345-1 (c).

ASME

Abbreviation for American Society of Mechanical Engineers.

Backhaul

Refers to a load of freight which permits a trucker to return to his home with a loaded truck, rather than an empty one.

Baffle

See 49 CFR 178.345-1 (c).

Baffle, Dished

A baffle with a concave/convex surface.

Barrel, Tank

Vessel weldment - shell and heads.

Bill of Lading

An itemized list of goods contained in a shipment

Billing

Preparation of the freight bill, the primary document for a common carrier shipment including a description of the freight, number of pieces and charges

Bogie

An auxiliary axle assembly having a fifth wheel used for purpose of converting a semitrailer to a full trailer. Dollies can be used to haul multiple trailers behind a single power unit. (Also referred to as dolly)

Blower

A device to deliver a volume of air at a certain pressure for use in unloading pneumatic tanks.

Break Bulk

To separate a composite load into individual shipments and route to different destinations

Break Bulk Terminal

A terminal designed to act as an intermediate sorting point for interregional freight. Freight from various end-of-line terminals is sent to a regional break bulk terminal to be combined into full trailers that the carrier then routes to a subsequent end-of-line terminals. Example: freight destined for Texas from a Binghamton, NY terminal might go to Stroudsburg, PA to be combined with other freight destined for Texas from other Eastern cities.

Brake Interlock, Parking

A system that applies the parking brakes upon actuation of an air interlock valve. This valve is typically actuated during the loading or unloading operation.

Bulkhead, Dished

A bulkhead with a concave/convex surface.

Bulkhead, Double

Two adjacent bulkheads forming a void space. Typically found when the bulkhead of one tank is next to the bulkhead of another tank. The area between the bulkheads typically forms a void.

Bulkhead, Flangeless Tank

An internal bulkhead that is formed with neither a knuckle radius or straight flange.

Bulkhead, Tank

See 49 CFR 178.345-1 (c) and 49 CFR 393.86.

Burner

Gas or liquid fueled burner for heating product in the tank.

Cap, Dust

Cover which mates with a male adapter.

Cap, Pipe

A cap which mates with the male threads of a pipe and which forms a liquidtight seal.

Capacity, Commodity

Total internal volume that does not include planned outage.

Capacity, Nominal

That compartmental volume to which a vessel is designed that does not include the planned stage.

Capacity, Shell

The absolute full capacity of a tank shell.

Carload

Single shipment of freight required to fill a rail car

Certification, Design

See 49 CFR 178.320 (a).

Certificate Holder

See Holder, Certificate

CFR

Acronym for Code of Federal Regulations.

Christmas Tree

See Vent.

Claim

(a) A demand made upon a transportation company for payment, due to loss or damage of freight alleged to have occurred while shipment was in possession of carrier.
(b) A demand upon a transportation company for refund of an overcharges from the erroneous application of rates, weights, and assessment of freight charges

Class I Motor Carriers *

Common or contract motor carriers of property that have average gross operating revenues of $5,000,000 or more annually from motor carrier operations

Class II Motor Carriers *

Common or contract motor carriers of property that have average gross operating revenues of $1,000,000 or more , but under $5,000,000 annually from motor carrier operations

Class III Motor Carriers *

Common or contract motor carriers of property that have average gross operating revenues of less than $1,000,000 annually from motor carrier operations

Class I Truck

Truck with gross vehicle weight (GVW) of 6,000 lbs or less

Class II Truck

Truck with gross vehicle weight (GVW) of 6,001-10,000 lbs

Class III Truck

Truck with gross vehicle weight (GVW) of 10,001-14,000 lbs

Class IV Truck

Truck with gross vehicle weight (GVW) of 14,001-16,000 lbs

Class V Truck

Truck with gross vehicle weight (GVW) of 16,001-19,500 lbs

Class VI Truck

Truck with gross vehicle weight (GVW) of 19,501-26,000 lbs

Class VII Truck

Truck with gross vehicle weight (GVW) of 26,001-33,000 lbs

Class VIII Truck

Truck with gross vehicle weight (GVW) of 33,001-10,000 or more lbs

COFC

Container on (rail) flat car. A form of intermodal movement of freight using a box suitable for use on rail cars, trailer frames, and container ships Containers come in many sizes. International containers which are used on ships usually have height and width of eight feet. Length can vary, but 20 and 40 foot lengths are the most common. US domestic containers are generally taller than international containers and may not always be suitable for ocean transportation.

Combination Vehicle

An equipment configuration which includes separate power unit (tractor) and at least one trailer

Commercial Trailer

A trailer used to handle freight in the transportation of goods for others; excludes house trailers, light farm trailers and car trailers

Commodity

Any article of commerce. Goods shipped

Common Carrier *

A transportation business that offers service to the general public. Interstate common carriers must hold a franchise issued by the ICC which limits service to a specific geographical area. Recent changes in regulation have blurred the distinction between common, private, and contract carriers. Term may be meaningless in the near future.

Competitive Rate *

A charge established to meet the competition of another transportation line

Connecting Carrier

A carrier which interchanges trailers with another for completion of shipments.

Contract Carrier *

For hire carriers which proved transportation under specific contracts or agreements that do not fall within the legal boundaries of common carriage. Recent changes in regulation have blurred the distinction between common, private, and contract carriers. Term may be meaningless in the near future.

Cock, Shut-Off

A device used to restrict or stop flow of air or liquid.

Compartment, Tank

The product carrying space of a tank motor vehicle. A cargo tank motor vehicle may have one or more such spaces. (See Tank, Cargo)

Compartment, Void

See Void Compartment.

Connection, Air

Fitting used to apply air pressure from source to vessel.

Connection, Loading/Unloading

See 49 CFR 178.345-1 (c).

Coupling, Pipe

See 49 CFR 178.345-1 (c).

Coupler, Cam & Groove

The female portion of a quick coupling device for pipe or hose ends.

CWT

Hundred weight, or one hundred pounds

Dam, Manhole

See Manhole, Dam

Deflector

A device placed inside a tank to change the flow direction during loading or unloading.

Degas

To purge compartments, voids, piping and components of dangerous vapors rendering the cargo tank safe for both hot and cold work.

Dip Stick

A separate measuring device used to determine the level of product in a tank.

Dip Tube

(1) A piping arrangement installed in a tank which will be pressure unloaded out of the top. (2) May also be a tube installed in a pressurized containers to gage the level of liquid.

DOT

Abbreviation for Department of Transportation.

DOT Specification

See Specification, MC/DOT.

Doubler Plate

A reinforcing pad, ring, collar or strap used to reinforce the shell or head.

Drain

A hole, pipe of hose used to gravity discharge liquid from an enclosed area such as a void, void compartment or manhole dam.

Drain, Flashing

See Flashing Drain

Emergency Valve

See Valve, Emergency

Engineer, Design Certifying

See 49 CFR 171.8.

Fill Cover, Spring Loaded

A fill cover designed to meet the requirements for the pressure-actuated vent in MC 306 cargo tanks, 49 Code of Federal Regulations, 178.341-4 (d) (2) and DOT 406 cargo tanks, 49 Code of Federal Regulations, 178.346-10 (d).

Fill Opening

An opening in top of a tank used for filling the tank. Usually incorporated in Manhole Cover. It may also be used for inspection.

Fire Tube

See Heating Tube.

Fitting, Clean Out

Fitting installed in the top of a tank to facilitate washing of the tank interior.

Fitting Guard

A structure to protect pipe fittings from damage.

Fitting, Terminal

The end fitting on a line.

Flange

See 49 CFR 178.345-1 (c).

Flange, Companion

See 49 CFR 178.345-1 (c).

Flange, Welded

See 49 CFR 178.345-1 (c).

Flash Point

Means the temperature at which the substance gives off flammable vapors which, in contact with a spark of flame, will ignite.

Flashing

Liquidtight rail on top of a tank which contains water and spillage and directs it to suitable drains, and may be combined with the overturn protection.

Flashing Drain

Metal or plastic tube which drains water and spillage from flashing to the ground.

Float Control

A switching device which opens a circuit when product being loaded into a tank reaches a pre-determined level.

FMCSA

Acronym that stands for Federal Motor Carrier Safety Administration

FMCSR

Acronym that stands for Federal Motor Carrier Safety Regulations, one of the most referenced set of publications in the transport industry

Gas Free

See Degas.

Gauge, Liquid Level

A device used to measure liquid commodity levels inside a cargo tank.

Gauge, Rotary

A gauge for determining the liquid level in a pressurized tank.

Girth Seam (A Circumferential Joint)

A welded joint around the entire circumference or partially around the circumference of the cargo tank joining two sections of the tank shell.

Head

(1) See Bulkhead, Tank. (2) Also terminology for pressure of a liquid caused by its own weight.

Head, Hemispherical

A head which is half a sphere in shape. Often used on MC 331 compressed gas cargo tanks and MC 338 cryogenic liquid cargo tanks.

Header

A pipe, tube, etc., that connects two or more pipes or tubes permitting the transfer of vapors or liquids to a common outlet. (Also see Manifold).

Heat Panel

A panel attached to the cargo tankxD5s shell by welding, bonding or banding used to heat the contents. May also be called steam panel.

Heating Tube

A tube installed inside a tank which is used to heat the contents. May also be called "fire tube" when the direct heat source is a flame.

Holder, Certificate

A moisture proof container provided for storage and easy access to trailer related literature such as licenses, registration, defect and maintenance information. (Formerly called Registration Holder and Defect Card Holder)

Hood, Vapor Recovery

A collecting device installed over tank vents or vapor valves for transfer of vapors during tank loading or unloading.

Hopper

Sloping panels at bottom of tank which direct dry bulk solids to the outlet piping.

Hose, Air Jumper

Hose connecting the truck tractor air supply to a trailer air line or hose.

Hose Carrier

Hose tube, hose trough, hose tube ends and hooks, mandrel and bracket.

Hose, Discharge

Hose used to unload the tank.

Hose Hooks

Hooks which carry the hose.

Hose Trough

An open type structure used on tank and bulk commodity trailers for the storage of cargo handling hoses.

Hose Tube

A housing used on tank and bulk commodity trailers for the storage of cargo handling hoses.

Indicator, Liquid Level

A device, usually a float or spew gauge, for determining the level of the product in a tank.

Indicators, Capacity

Device installed on tank to indicate capacity at a specific level. (Sometimes called markers).

Inspection Agency, Authorized

See 49 CFR 171.8.

Inspector, Authorized

See 49 CFR 171.8.

Inspector, Registered

See 49 CFR 171.8.

Interlock, Parking

See Brake Interlock, Parking

Jacket

A metal cover which protects the tank insulation.

Label, MC/DOT Tank Certification

See Plate, MC/DOT Tank Certification.

Lading, Hazardous

See 49 CFR 178.345-1 (c).

Line Aeration

Line supplying air to the Aerator.

Line, Blowdown

A line through which tank air pressure is released by means of the blowdown valve.

Line Charging

See 49 CFR 178.345-1 (c).

Line Crossover

Installed in tank piping system to allow unloading from either side of tank.

Line, Pipe

A product inlet or outlet line.

Line, Pump Off

A pipeline which usually runs from the tank discharge openings to the front of the trailer. Most pumps are mounted on the tractor.

Line, Vapor Recovery

A line which connects the vapor recovery hood to a convenient location for attachment to a vapor recovery hose.

Lining

The material applied to the inside of a tank shell surface to protect the tank shell from its contents.

Manhole

An opening usually equipped with removable cover and large enough to admit a man into a cargo tank or dry bulk trailer; may incorporate vents, fill opening and other devices.

Manhole, Dam

Liquid tight box for the collection of spillage (also called spill box, flashing box or crows nest).

Manifold

Used to join a number of pipelines to a common inlet or outlet. (Also see Header).

Manufacturer, Cargo Tank

See 49 CFR 178.320 (a).

MAWP

See Pressure, Maximum Allowable Working.

MC Specification

See Specification, MC.

Modification

See 49 CFR 180.403.

Nameplate

The NHTSA certification label containing the manufacturerxD5s name and vehicle identification number or for cargo tank vehicles manufactured prior to the NHTSA certification plate containing the manufacturerxD5s name and cargo tank serial number. (See Plate, MC/DOT)

Nozzle, Tank

See 49 CFR 178.345-1 (c). The pipe or tubular section of the nozzle is short and may be threaded instead of flanged.

Outage

The space that remains unfilled in a cargo tank after being loaded with payload.

Outlet

See 49 CFR 178.345-1 (c).

Outlet, Loading/Unloading

See 49 CFR 178.345-1 (c).

Outlet, Vapor

The terminus of the vapor recovery line.

Outrigger

Structural load-carrying members attached to and extending outward from the main longitudinal frame members of a tank trailer, which cradle the tank shell or stiffeners. Sometimes called Cradle End.

Overturn Protection

Protection for fittings on top of a tank in case of rollover. May be combined with flashing rail or manhole dam. Also known as Rollover Damage Protection. See 178.345-8 (c) for DOT 400 Series cargo tanks.

Pads

A piece of material attached to the tank shall to which various attachments are made.

Pipe

See Line, Pipe.

Plate, MC/DOT Tank Certification

(As required by the Research and Special Programs Administration) Metal plate permanently affixed to a cargo tank and located near the front left side of the cargo tank stating that the cargo tank conforms with all applicable Federal Hazardous Materials Regulations in effect on the date of the original manufacture or modification.

Platform

Area on top of the tank near the manhole designed for a person to stand upon.

Pressure, Inspection

See 49 CFR 178.345-1 (c).

Pressure, Maximum Allowable Working

See 49 CFR 171.8 and 178.345-1 (c).

Pressure, Test

See 49 CFR 178.345-1 (c).

Protection, Bottom Damage

Device which protects outlets and piping located in the lower one-third of the cross section perimeter from damage during an accident. See 178.345-8 (b) for DOT 400 series cargo tanks.

Protection Device, Rear-End Tank

See 49 CFR 178.345-1 (c). (Also see Bumper, Rear).

Protection Overturn

See Overturn Protection.

PSIA

Pressure expressed in pounds per square inch absolute. Add approximately 14.7 to gauge reading to give absolute reading.

PSIG

Pressure expressed in pounds per square inch gauge. Gauge pressure is the difference between atmospheric pressure and pressure being measured.

PTO

Abbreviation for Power Take Off.

Rebarrelling

See 49 CFR 180.403.

Repair

See 49 CFR 180.403

Replacement Barrel

To completely replace the vessel weldment of an existing cargo tank with a newly manufactured vessel weldment using only new materials.

Ring Stiffener

Structure encircling the tank either inside or outside the tank shell to maintain the shape of the tank and its structural stiffness when under pressure/vacuum.

Rollover Protection

See Overturn Protection

RP

Abbreviation for Recommended Practice.

Rupture Disc (A frangible vent)

A safety device which fails at a predetermined pressure and thus protects a pressure vessel from being over pressurized. (Also see Vent).

Sacrificial Device

See 49 CFR 178.345-1 (c). (Also see Shear Section).

Seam, Girth

See Girth Seam.

Sensor, High Level

A liquid actuated sensor installed in a secondary shut-off system. Also, this sensor is sometimes used as a primary shut-off system. The signal from this sensor stops the loading pumps or closes the emergency valve upon overfill. (See Shutoff System, Secondary).

Sensor, Liquid Level

See Indicator, Liquid Level.

Sensor, Retained

A liquid actuated sensor installed in the bottom of a compartment to indicated the presence of liquid.

Shear Section, DOT 400 Series Cargo Tanks

See 49 CFR 178.345-1 (c). (Also see Sacrificial Device).

Shear Section, MC 300 Series Cargo Tanks

A machine groove located outboard of an emergency valve seat and within 4 inches of the vessel which should break under strain and leave the emergency valve seat and its attachment to the vessel and the valve head intact and capable of retaining product.

Shell, Tank

See 49 CFR 178.345-1 (c).

Shutoff System, Secondary

A system that provides overflow protection during bottom loading.

Slope

Difference in height between highest and lowest points of the tank bottom.

Slope Sheet

Panels located at each end or side of compartment which direct product by gravity to hoppers.

Specification, MC/DOT

The U.S. DOT Motor Carrier Specification for tank vehicles authorized to carry specified hazardous materials.

Splash Guard

A device which deflects road spray.

Stack

The exhaust pipe for tanks with burners.

Steam Panel

See Heat Panel.

Stick, Dip

See Dip Stick.

Stiffener, Ring

See Ring Stiffener.

Stretching

See 49 CFR 180.403.

Structure, Connecting

See 49 CFR 178.345-1 (c).

Subframe

The frame to which the undercarriage is attached.

Sump

See 49 CFR 178.345.1 (c).

Sump, Cleanout

The low point of a tank which may be opened for cleaning.

Swivel Joint

A movable metallic product transfer conductor usually used on discharge lines to eliminate the bending or twisting of hoses.

Tank

See 9 CFR 178.345-1 (c).

Tank, Cargo

See 49 CFR 171.8 and 178.320 (a).

Tank Design Type

See 49 CFR 178.320 (a).

Tank, DOT 406

Tank built after October 1, 1990, meeting US DOT specifications DOT 406 as defined in 49 Code of Federal Regulations 178.346. This tank is typically used to carry gasoline, fuel oil, alcohol, or other liquid flammables. This tank is typically constructed of aluminum and designed with an elliptical cross section.

Tank, DOT 407

Tank built after October 1, 1990, meeting US DOT specifications DOT 407 as defined in 49 Code of Federal Regulations 178.347. This tank is typically used to carry solvents, plasticizers, casinghead, gas, etc. This tank is typically constructed of stainless steel or aluminum and designed for pressure of at least 25 psig.

Tank, DOT 412

Tank built after October 1, 1990, meeting US DOT specifications DOT 412 as defined in 49 Code of Federal Regulations 178.348. This tank is typically used to carry corrosives. This tank is typically constructed of stainless steel or carbon steel and designed for a pressure of 35 psig.

Tank, Dry Bulk

A tank typically constructed of aluminum or carbon steel to carry dry bulk commodities such as cement, fertilizer, sand, plastics, grain, etc. with typical densities ranging from 18 to 125 pounds per cubic feet. This tank is typically designed for an unloading pressure of 15 psig.

Tank, Frac

A portable storage tank used to hold flushing or fracing fluid at an oil well site. Characterized by a large, rectangular cross section, a single axle suspension, no landing gear, and a front winching bar.

Tank, Fuel

Tank used to hold fuel for the burners.

Tank, Hot Products

A tank typically insulated to handle asphalt and other products at a temperature over 300xA1 F. This tank is typically constructed of aluminum, steel, or stainless steel and designed for atmospheric pressure.

Tank, MC 304

Tank built prior to December 1, 1967 to old US DOT Specifications MC 304 for the transportation of flammable liquids or poisonous liquids. This tank was constructed of steel and aluminum with a design pressure of at least 25 psig. This tank is a predecessor of the MC 307 tank.

Tank, MC 305

Tank built prior to December 1, 1967 to old US DOT Specification MC 305 for the transportation of flammable liquids or poisonous liquids. This tank was constructed of aluminum and designed for atmospheric pressure. This tank is a predecessor of the MC 306 tank.

Tank, MC 306

Tank built after December 1, 1967 and prior to April 21, 1994, meeting US DOT Specification MC 306 as defined in 49 Code of Federal Regulations 178.341. This tank is typically used to carry gasoline, fuel oil, alcohol, or other liquid flammables. This tank is typically constructed of aluminum and designed for atmospheric pressure. This tank is a predecessor of the DOT 406 cargo tank.

Tank, MC 307

Tank built after December 1, 1967 and prior to April 21, 1994, meeting US DOT Specification MC 307 as defined in Code of Federal Regulations 178.342. This tank is typically used to carry solvents, plasticizers, casinghead gas, etc. This tank is typically constructed of stainless steel and designed for a pressure of at least 25 psig. This tank is a predecessor of the DOT 407 cargo tank.

Tank, MC 311

Tank built prior to December 1, 1967 to old US DOT Specification MC 311 for the transportation of corrosives. This tank was constructed of steel or aluminum. This tank is a predecessor of the MC 312 tank.

Tank, MC 312

Tank built after December 1, 1967 and prior to April 21, 1994, meeting US DOT Specification MC 312 as defined in 49 Code of Federal Regulations 178.343. This tank is typically used to carry corrosives. This tank is typically constructed of stainless steel of carbon steel and designed for a pressure of 35 psig. This tank is a predecessor of the DOT 412 cargo tank.

Tank, MC 330

Tank built prior to December 1, 1967 to old US DOT Specification MC 330 for the transportation of compressed gases. This tank was typically constructed of quenched and tempered or carbon steel for a pressure of 250 to 265 psig. This tank is a predecessor of the MC 331 tank.

Tanks, MC 331

Tank meeting US DOT Specification MC 331 as defined in 49 Code of Federal Regulations 178.337. This tank typically used to carry anhydrous ammonia, propane, or other liquefied or pressurized gases. This tank is typically constructed of quenched and tempered or carbon steel and designed for a pressure of 265 psig.

Tank, MC 338

Tank built after October 1, 1984, meeting US DOT Specification MC 338 as defined in 49 Code of Federal Regulations 178.338. This tank is insulated and designed to carry cryogenic liquids.

Tank, Non-Spec

A tank not meeting one of the US DOT Specifications.

Tank, Sanitary

A tank typically insulated to carry milk, vinegar, vegetable oils, syrups, and other food products. This tank is typically constructed of stainless steel and designed for atmospheric pressure.

Tank, Self Supporting

A tank trailer whose shell is the structural support member for the vehicle.

Tank, TOFC

A tank meeting Association of American Railroads Specification M-931, Appendix F. This tank is a MC 307, MC 312, DOT 407, DOT 412 or IMCO Type 4 tank constructed of steel with a minimum design pressure of 35 psig. This tank trailer is for trailers on railroad flat car service.

Tank, Vacuum

Tank equipped with a pump to reduce the pressure in the tank to much less than atmospheric pressure. This reduced pressure of xD2vacuumxD3 is used for loading the tank. (See Tank, Waste). Also see 49 CFR 178.345-1 (c).

Tank, Variable Specification

See 49 CFR 178.345-1 (c).

Tank, Washout

A tank holding solvent for cleaning pump and discharge hose.

Tank, Waste

Tank designed to transport waste consisting of liquid and/or solids. Tank may have a full opening rear head. Tank may be equipped for vacuum loading.

TB

Abbreviation for Technical Bulletin.

Toughness of Material

See 49 CFR 178.345-1 (c).

Transition

That section of a tank which joins two unequal cross sections.

Tube, Dip

See Dip Tube.

Valve, Blow Down

A manually operated valve whose function is to quickly reduce tank pressure to atmospheric.

Valve Box

See Fitting Guard.

Valve Check

A valve built to provide free fluid flow in one direction only.

Valve, Crossover

A valve which allows the discharge to be directed to either side of the tank via the crossover line.

Valve, Emergency

A remote controllable valve installed in a tank outlet sump or its companion flange which is capable of self-closing in the event of an emergency. Also known as Valve, Internal Self-Closing Stop.

Valve, Emergency, Operator

A device used to open and close emergency valves.

Valve, Emergency, Remote Control

A secondary closing means, remote from tank discharge openings, for operation in event of fire or other accident.

Valve, Excess Flow

A valve which automatically closes at its rated flow of gas or liquid.

Valve, Internal

See Valve, Emergency.

Valve, Internal Self-Closing Stop

See 49 CFR 178.345-1 (c). Also known as Valve, Emergency.

Valve, Loading/Unloading Stop

See 49 CFR 178.345-1 (c).

Valve, Outlet

The valve which is farthest downstream in a tank piping system to which the discharge hose is attached.

Valve, Outlet Stop

See 49 CFR 178.345-1 (c).

Valve, Pressure Relief

Valve with predetermined start to discharge pressure to protect the tank from being over-pressurized. (Also see Vent, Pressure Actuated).

Valve, Product

Valve for holding or releasing product into or out of the tank.

Valve, Proportioning

A valve used to balance or divide the air supply between the aeration system and the discharge manifold.

Valve, Pump Off

Valve on pump-off line which when open allows the product to be pumped out of the tank.

Valve, Sampling

Valve which when open allows a sample of product to be collected.

Valve, Self-Closing Stop

See 49 CFR 178.345-1 (c).

Valve, Self Contained Shut Off

An emergency valve that closes upon receiving a signal from the high level sensor.

Valve, Shuttle

A connective valve which selects one of two circuits, whichever supplies the higher pressure.

Valve, Splitter

A valve installed to divide pipeline manifold.

Valve, Stop

See 49 CFR 178.345-1 (c).

Valve, Vapor Recovery (See Vent, Vapor Recovery)

A valve typically found in a vapor recovery system to control the flow of vapors. Also a vent that opens and closes with the actuation of the emergency valve permitting the transfer of vapors when in the open position. (Typically opens inward into the tank compartment).

Valve, "Y"

A valve which can be used for both bottom loading and off-loading. Incorporates American Petroleum Institute standard adapter.

Vapor Free

See Degas.

Vehicle, Cargo Tank Motor

See 49 CFR 171.8 and 49 CFR 178.320 (a).

Vehicle Assembly, Cargo Tank Motor

See 49 CFR 107.502.

Vehicle, Multi-Specification Cargo Tank Motor

See 49 CFR 178.345-1 (c).

Vent

Devices which control or limit tank pressure. Some type are: 1. Outbreathing (pressure relief) 2. Inbreathing (vacuum relief) 3. Fusible (opens at elevated temperature) 4. Christmas tree (slang for a combination vent) 5. Rupture disc ( See Rupture Disc)

Vent, Overflow

Vent on hot products tanks for overflow of product due to surge and/or expansion.

Vent, Pressure Actuated

A normally-closed, spring-loaded vent for pressure protection. Required on MC 306 cargo tanks, 49 Code of Federal Regulations, 178.341-4-(d); MC 307 cargo tanks, 178.342.4 (c); MC 312 cargo tanks, 178.343-4 (a); DOT 406 cargo tanks, 178.346-10 (d); DOT 407 cargo tanks, 178.347-10 (d); and DOT 412 cargo tanks, 178.348-10 (d).

Vent, Vacuum Breaker

A spring-loaded normally closed vent for vacuum protection.

Vent, Vapor Recovery

A vent that opens and closes with the actuation of the emergency valve permitting the transfer of vapors when in the open position. (Typically opens outward from the tank compartment).

Vents, Normal

A pressure-vacuum vent specified in 49 Code of Federal Regulations, 178.341-4 (b) and (c) and required in each MC 306 compartment and may be installed in each DOT 406 cargo tank.

Void

An enclosed space in a vessel which does not contain product and has no manhole. Also see 49 CFR 178.345-1 (c).

Void Compartment

A void equipped with access manhole.

Walkway

That portion top of a tank designed for personnel to walk on.

Wall, Cargo Tank

See 49 CFR 178.320 (a).

Weight per Gallon, Allowable

The maximum density, as pounds per gallon, of products which be loaded into a given tank without exceeding the load limits of the tank container or tank trailer.

Weldment, Vessel

The entire tank vessel and welded appurtenances such as nozzles, manholes, flanged and threaded fittings, etc. Bolted-on appurtenances are not included.