Confinement Devices cont'd - doe-std-1128-98

DOE-STD-1128-98

Vacuum systems connected to a glove-box should be designed to prevent

an evacuation and possible implosion of the glove box.

Any gas-supply system connected directly to a glove box should be

designed to prevent pressurization, flow in excess of the exhaust

capacity, and backflow.

Flammable or combustible gases should not be used in glove boxes but,

if required, should be supplied from the smallest practical size of

cylinders. Flammable gas piped to a plutonium processing building

should not enter the building at a pressure exceeding 6-in. water.

Vacuum pump exhaust should be filtered and exhausted to the glove box

or other acceptable exhaust system.

If process water is provided to a glove box and the water must be valved

on when the box is unattended, a system should be installed to

automatically close a block valve in the water-supply line if a buildup of

water is detected on the box floor or in the box sump.

Process piping to and from glove boxes should be equipped with

backflow prevention devices and should be of welded stainless steel

construction. Vacuum breaker-type devices are generally more reliable

than other types.

Glove-box components, including windows, gloves, and sealants, should

be of materials that resist deterioration by chemicals and radiation.

Glove ports should be designed to allow for the replacement of gloves

while maintaining control of radioactive material. The ports should be

located to facilitate both operating and maintenance work. The need for

two-handed operation, depth of reach, mechanical strength, and

positioning with respect to other ports should be considered in the

design. Covers or plugs should be provided for each port. The covers or

plugs should provide shielding equivalent to the glove-box walls.

Automatic glove-changing systems should be considered.

Bag-out ports, sphincter seals, and air locks should be designed and

installed to facilitate the introduction and removal of equipment and

supplies without compromising contamination control. Air-lock gaskets

at the bottom rim should be protected from any physical damage

potentially incurred by removing items. Air locks should be designed to

be at negative pressure with respect to the workstation and positive

pressure with respect to the glove box.

Windows should be constructed of noncombustible or fire-resistant

materials that resist scratching, breaking, and radiation degradation. Wire

glass should be considered except where precluded by requirements for

visual acuity. In those instances, tempered or safety glass may be

suitable. Windows should be kept as small as possible while still meeting

visual requirements. A push-in window design should be considered for

C-18