Section 2.
DOORS AND CLOSURES
1.
DOORS AND CLOSURES. Doors and closures provide the means for personnel
to enter into or egress from a PV. They also provide for the moving of
equipment into and out of a PV. When doors or closures are arranged so that
personnel, equipment or animals can be transferred into or out. of a vessel
without loss of internal pressure, they are called "locks."
There are two basic types of doors and closures: those that are sealed by
pressure and those that have a means of locking the door against pressure.
Each door requires careful design, fabrication, installation testing and
maintenance to provide safe, easy and rapid operation from inside and outside
the PV without the use of special tools. The door hinging, closing, locking
and sealing elements must be resistant to and protected from abuse due to
rough handling or possible accidents. A typical recompression chamber door
is shown at Figure 3-18. Doors may be fabricated of one of more pieces, of
flat plate or of dished plate with pressure on either the convex or concave
side. Whenever practical a door should be arranged so that the contained
pressure holds the door closed, and if possible no dogging or latching
mechanism should be used other than a handle to pull the door closed or open.
A typical Service Lock is shown at Figure 3-19. Note that this lock has two
types of doors. The door inside the chamber is sealed by pressure and the
outer door is sealed by swing bolts.
2.
SIZE REQUIREMENTS. The proper sizing of doors is important for manned
facilities. Doors which are unnecessarily large reduce chamber strength and
are excessively heavy while doors which are too small adversely affect
chamber utilization. The human engineering of hyperbaric chamber doors is a
difficult problem because they are nearly always round with an extremely
thick, sharp-edged threshold. Although there is little the designer can do
to rectify this, he can make use of statistical information to size doors
properly for the chamber crew members.
a.
Anthropometric Data. Tables 3-7 and 3-8 give some basic
anthropometric data useful in sizing doorways and for other design
considerations in hyperbaric chambers. Additional human factors information
is available in MIL-STD-1472 (see reference 5, Human Engineering Design
Criteria).
(1) Vertical doors. From Figure 3-20, which was scaled from 95th
percentile data in Table 3-8, it can be seen that a diameter of 36 to 40
inches provides reasonable clearance for convenient entry through a vertical
door.
(2) Horizontal doors. The 95th percentile shoulder breadth is
about 20 inches. Because the body can be supported with the arms essentially
vertical, a reasonable minimum diameter for a vertical entry door is 22 to 24
inches.
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