Glossary

AASHTO

Specific engineered load bearing measurement defined as follows: 16,000 lbs. over 10″ x 20″ area + 33% impact factor. (Note: AASHTO stands for American Association of State Highway and Transportation Officials.)

AIRCRAFT LOAD HATCH

A hatch that is designed for load criteria based on a linear reduction from 280 p.s.i. for a 2 foot span to 80 p.s.i. for a 10 foot span (ref: FAA AC 150/5320-6c). It is designed for the airside at airports, marine ports and other areas of extremely heavy loading conditions.

ANGLE FRAME

The basic frame is constructed out of angle lengths of metal. For aluminum doors an extruded angle is used. For steel doors a structural angle is used. Angle frame doors have either an anchor flange along their base or welded strap anchors so that the frame will be securely held in place when cast into concrete. Angle frame doors allow water runoff to enter the vault area.

BASIN COVER

A metal plate (usually circular, but can be rectangular) that is bolted along a small portion of its perimeter to the opening lip of the existing structure (i.e., basin or vault). The remaining portion of the cover plate serves as a lid and opens 180 degrees.

BASIN COVER WITH INTEGRAL SINGLE DOOR

A metal plate (usually circular, but can be rectangular) that is bolted around its perimeter to the opening lip of the existing structure (i.e., basin or vault). Within the metal plate is a rectangular framed door to permit access into the basin.

CAST INTO CONCRETE

A hatch is “cast into concrete” when its frame is positioned over a vault or into a form, a concrete slab is poured around it and the concrete is allowed to set or harden.

CLEAR OPENING

The width (span) and length dimensions measured in inches (or millimeters) of unobstructed access through a hatch’s frame. The clear opening “C” dimension corresponds to the frame’s span, and the clear opening “D” dimension corresponds to the frame’s length.

DIRECT TRAFFIC DOORS

Steel or stainless steel doors that are designed to support an AASHTO H20-44 wheel load (16,000 pound over 10″ x 20″ area + 33% impact factor) for use in roadways with a maximum posted speed limit of 70 miles per hour.  Consult the manufacturer for use in roadways inside or leading into: seaport facilities, military bases, airports, landfills, freight terminals, bus terminals and any other area where there is continuous commercial vehicle traffic.

EXISTING OPENING

An opening that already exists (e.g., a rectangular hole in cured concrete or in a wooden floor).

FLOODTIGHT / GASTIGHT

A hatch frame with a built-in gasket that creates a floodtight / gastight seal against the hatch cover when the door is in its closed position. This seal can withstand the water pressure created by either 10 or 25 feet of standing water (i.e., flood conditions). The seal is also effective at preventing the passage of odors or gases from the area below the door where there is no positive pressure below the cover.

FLOODTIGHT RETROFIT

A hatch frame with a built-in rubber gasket that creates a floodtight / gastight seal against the hatch cover when the door is in its closed position. This seal can withstand the water pressure created by 10 feet of standing water (i.e., flood conditions). The seal is also effective at preventing the passage of odors or gases from the area below the door where there is no positive pressure below the cover.

FRAME OPENING

The inside dimensions measured in inches (or millimeters) from the inside face of the frame to the opposite inside face of both its short and long dimensions.

LOADING

The amount of weight a hatch cover can support – measured in either pounds per square foot (p.s.f.) or pounds per square inch (p.s.i.).

METAL

USF Fabrication, Inc. uses a variety of metals including aluminum, steel and stainless steel to manufacture hatches and miscellaneous products. Specific metal alloys are available as per the customer’s specification.

OCCASIONAL TRAFFIC DOORS

Aluminum, steel or stainless steel doors that are designed to support an AASHTO H20-44 wheel load (16,000 pound over 10″ x 20″ area + 33% impact factor) in off-street locations on an occasional basis (e.g., grassy areas next roadways). These type doors are not designed to withstand the repeated impact of direct traffic doors (see above definition for direct traffic).

OVERALL SIZE

The outside dimension measured in inches (or millimeters) from opposite sides of a hatch’s frame. The overall width, or “E” dimension, corresponds to the frame’s span-Side A, and the overall length, or “F” dimension, corresponds to the frame’s length-Side B.

PARKING LOT DOORS

Galvanized steel or stainless steel doors that are designed to support an AASHTO H20-44 wheel load (16,000 pound over 10″ x 20″ area + 33% impact factor) in parking lots where the posted speed limit is 15 mph or less. These type doors are not designed to withstand the repeated impact of direct traffic doors (see above definition for direct traffic).

RECESSED

A hatch cover that is 1/8 to 1-inch lower than its surrounding frame. The particular design allows tile or carpet to be to be affixed (glued or mortared) to the cover so that the surface level of the tile or carpet on the door is flush with the surrounding floor.

RETROFIT

To refit something (e.g., hatch) onto something else (e.g., an existing framed hole) that already exists.

ROUND FRAME

The basic frame is constructed out of structural angles that are rolled into a circle. Angle frame doors have an anchor flange along their base so that the frame will be securely held in place when cast into concrete.

TROUGH

The basic frame is constructed so that a trough is created to channel water towards a drain hole where it is discharged into a pipe. For aluminum doors the trough frame is constructed of extruded material. For steel doors the trough frame is constructed of structural shapes that are welded together. The trough frame doors have an anchor flange along its base so that the frame will be securely held in place when cast into concrete.

WATERTIGHT

Within the waste water industry the term “watertight” — as pertaining to access doors — means that the door has a “drainable” frame commonly referred to as a channel or trough or moat type frame. This type frame is designed to collect water running off the cover so it can be directed to a drain and not enter the vault area below the door.