MIL-HDBK-1191
temporary auxiliary source of supply. Valving and pressure control
devices shall be in accordance with NFPA 99 (reference 9r).
System Demand. The piping system shall be designed to
9.6.20.3
deliver 20 L/min (0.7 cfm) at the outlet, utilizing a 100% usage factor
for outlets in critical areas and the factors in Table 9-13 for outlets
in other areas. Historical usage data from replaced or similar MTF's may
be used as a guideline when determining system demand instead of the
method presented in 9.6.20.4. Refer to 9.6.20.5 below for additional
design considerations for determining the
required capacity of liquid bulk tanks.
TABLE 9-13
OXYGEN SYSTEM UTILIZATION FACTORS
Percent Usage
Number of Outlets
1--3
100
4-12
75
13-20
50
21-40
31
41 or more
25
Storage Capacity Sizing Method. In the absence of available
9.6.20.4
historical oxygen consumption data, Table 9-14 shall be used in
estimating required system storage capacity for MTF's having large in-
patient populations (e.g. hospitals and medical centers). For facilities
with predominantly outpatient functions, designers shall work with the
Using Service to estimate consumption rates and appropriate storage
capacities.
TABLE 9-14
CYLINDER MANIFOLD SYSTEMS
1
Minimum Number of Cylinders
Number of Beds
1 - 50
8
51 - 75
12
76 - 100
16
101 - 125
20
126 - 150
24
Requires special study 2
Over 150
1
Per bank of "H" cylinders.
2
The special study shall include an analysis of an
appropriate diversity factor and the cost effective option
between cylinder and bulk storage.
Little published data is available at present to help establish oxygen
consumption on a per-outlet basis in predominantly outpatient facilities.
Oxygen usage rates and procedural duration vary widely depending upon the
clinical application. For example, a typical surgical procedure begins
with a preparatory oxygenating period of up to 10 minutes at a
consumption of 6 to 8 L/min (0.2 to 0.3 cfm). During the actual
procedure, the usage rate decreases to 1 to 3 L/min (0.04 to 0.11 cfm)
for a time period ranging from a fraction of an hour to several hours
depending upon the nature of the surgery. A post-surgical de-
nitrogenizing period of up to 10 minutes at 6 to 8 L/min (0.2 to 0.3 cfm)
follows. Post-operative demands range as high as 18 L/min for recovery
rooms with an average stay that ranges from 30 to 120 minutes. Oral
9-30
Previous Page
