Info

12:00

10:34

6:13

4:33

3:31

2:45

2:08

1:38

1:13

0:50

0:31

40 6:07 5:04 4:18 3:42 3:12 2:47 2:24 2:05 1:47 1:31 1:16 1:03 0:50 0:38 0:27 0:17

40 6:07 5:04 4:18 3:42 3:12 2:47 2:24 2:05 1:47 1:31 1:16 1:03 0:50 0:38 0:27 0:17

50 3:10 2:23 2:17 2:03 1:51 1:39 1:28 1:18 1:08 0:59 0:50 0:42 0:34 0:26 0:19 0:12

60 2:30 1:40 1:30 1:20 1:14 1:11 1:04 0:57 0:50 0:43 0:37 0:31 0:25 0:20 0:14 0:09

70 2:10 1:20 1:10 1:05 1:00 0:51 0:50 0:45 0:39 0:34 0:30 0:25 0:20 0:16 0:11 0:07

80 1:10 1:05 1:00 0:55 0:50 0:45 0:39 0:37 0:33 0:29 0:25 0:21 0:17 0:13 0:10 0:06

90 1:00 0:55 0:50 0:45 0:42 0:40 0:32 0:31 0:28 0:24 0:21 0:18 0:14 0:11 0:08 0:05

100 0:50 0:45 0:42 0:40 0:38 0:35 0:30 0:27 0:24 0:21 0:18 0:15 0:13 0:10 0:07 0:05

110 0:45 0:40 0:37 0:35 0:33 0:30 0:25 0:24 0:21 0:19 0:16 0:14 0:11 0:09 0:06 0:04

120 0:40 0:38 0:35 0:33 0:30 0:28 0:25 0:20 0:19 0:17 0:15 0:12 0:10 0:08 0:06 0:04

130 0:35 0:34 0:32 0:30 0:28 0:25 0:23 0:20 0:16 0:15 0:13 0:11 0:09 0:07 0:05 0:03

140 0:35 0:30 0:28 0:27 0:25 0:23 0:20 0:19 0:16 0:13 0:12 0:10 0:08 0:07 0:05 0:03

150 0:30 0:29 0:27 0:25 0:23 0:20 0:19 0:18 0:16 0:13 0:11 0:09 0:08 0:06 0:04 0:03

160 0:30 0:28 0:25 0:24 0:23 0:20 0:19 0:18 0:15 0:13 0:10 0:09 0:07 0:06 0:04 0:03

170 0:25 0:24 0:23 0:22 0:20 0:19 0:18 0:17 0:15 0:13 0:10 0:08 0:07 0:05 0:04 0:03

Residual Nitrogen Times (Minutes)

* No RNT After This Time

The Diving Supervisor and medical personnel should recognize that a diver who has been breathing a mixture with ppO2 lower than 0.6 ata for any length of time may have a greater risk of developing decompression sickness. Such a diver requires observation after surfacing, but need not be treated unless symptoms of decompression sickness occur.

17-10.5 Emergency Breathing System (EBS). The Emergency Breathing System provides an alternate breathing source for decompressing diver(s) in the event of a MK 16 failure. The two types of EBS available for use are EBS Type I and EBS Type II MK 1 Mod 0. The systems have been designed and tested as an accurate method for topside to control and monitor breathing gas being supplied to a diver(s) during decompression. The EBS shall be deployed whenever MK 16 decompression diving is anticipated. In the event of MK 16 failure or malfunction, the diver(s) will transfer to the EBS as soon as possible and continue to use the EBS to complete the decompression profile. It is to be used only for its designed purpose as discussed in paragraph 17-10.3 as an emergency breathing source and not as a surface-supplied diving system.

17-10.5.1 EBS Type I. The EBS type I was designed and is intended to be used only in support of diving up to 200 fsw. NAVSEA Operation and Maintenance manual S9592-AN-MMO-010 provides detailed equipment descriptions, reference data, and information on operation and maintenance. This type of EBS is a non-certified system (Figure 17-8)

17-10.5.2 EBS Type II MK 1 Mod 0. The EBS II is a certified surface-supplied, in-water emergency life-support system, with capabilities to support two divers during decompression for dive profiles to 300 fsw (Figure 17-9). The EBS II enables voice communication capabilities between topside personnel and divers while the divers are using the MK 24 FFM (Figure 17-10). PEO MINEWAR technical manual SS600-AL-MMA-010 provides detailed equipment descriptions, reference data, and information on operation and maintenance.

17-10.5.3 Required Gas Supply for the EBS. When a decompression dive is planned, the Diving Supervisor must calculate the volume of gas required should a diver be required to breathe from the EBS throughout decompression.

17-10.5.3.1 Calculating EBS Gas Requirements. The following steps may be used to calculate EBS gas requirements (Figure 17-11):

1. Determine decompression profiles from appropriate closed-circuit mixed-gas UBA decompression tables using 0.7 ata constant partial pressure of oxygen.

2. Multiply the time of each decompression stop by the gas consumption rates (scfm) in Table 17-11 to obtain total volume required per stop. Table 17-11 assumes a light work rate (gas consumption = 0.63 acfm).

Figure 17-8. EBS Type 1.

3. Total the volumes required per stop to obtain total volume for decompression. The total should be rounded up to the nearest whole scf.

4. Multiply the total volume for decompression by a safety factor of 10 percent and add the product to the volume for decompression for total air volume required.

The volume of gas available in the EBS I may be obtained from Table 17-12 when twin 80-cubic foot scuba bottles are employed or from the following formula when other EBS configurations are used.

FV x N x (Pi -PR) EBS Volume Available (SCF) = —-——1-—

Where:

Figure 17-9. EBS II Major Assemblies and Ancillary Equipment. CHAPTER 17 — Closed-Circuit Mixed-Gas UBA Diving

Figure 17-10. Full Face Mask MK 24 MOD 0.

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