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

DOE-STD-1128-98

Ergonomics should be considered in designing the height of glove-box

ports and access to inner surfaces and equipment.

Each glove box should be equipped with an audible alarm that can be

tripped to signal radiological problems. Individuals should be able to

activate the alarm without removing their arms from the glove box. The

alarm should sound in a continuously occupied area where it should, as a

minimum, identify the room in which the alarm originated.

A HEPA filter should be installed on the air inlet to the glove box if

required to prevent the backflow of contamination. Prefilters should be

installed upstream of the HEPA filter where appropriate. The exhaust

outlet for each glove box should have HEPA filters to keep the

ventilation ductwork clean. This filter should not be counted as a formal

HEPA stage and need not meet all the test capabilities for HEPA

filtration; however, it should be tested prior to installation. Push-through

filter change-out systems should be used if possible. The HEPA filters

downstream of the glove box should be readily accessible for filter

change-out and testable.

Glove-box air inlets and inlet filters should be protected or oriented to

prevent inadvertent entry of water into the box (e.g., a fire-sprinkler

system discharge or water-line leak).

Glove boxes should be designed to operate at a negative pressure (0.75

0.25 in. water gage (WG)) with respect to the room in which they are

operated. Differential pressure gauges should be installed on each glove

box or integrally connected series of glove boxes. During abnormal

conditions, control devices to prevent excessive pressure or vacuum

should be either positive-acting or automatic or both. The ventilation

system should be designed to provide and maintain the design negative

pressure during normal operations and the design flow through a breach.

There should be exhaust capacity on demand that will promptly cause an

inflow of air greater than 125 linear ft/min through a breach of at least a

single glove-box penetration of the largest size possible. Filters,

scrubbers, demisters, and other air-cleaning devices should be provided

to reduce the quantities of toxic or noxious gases and airborne

particulates that enter the ventilation system prior to its entry into the

exhaust system.

Each glove box or integrally connected series of glove boxes should be

equipped with an audible alarm that alerts personnel when a system

pressure or vacuum loss is occurring. The alarm should be set at -0.5-in.

WG relative to the room in which the glove box is located.

The number of penetrations for glove-box services should be minimized.

The fittings should provide a positive seal to prevent the migration of

radioactive material. For the same reason, penetrations for rotating shafts

should not be permitted except where rotating shafts have seals. Seals for

rotating shafts are very reliable and are preferred to motors inside the

glove box.

C-17