Home
gpo.gov
govinfo.gov

e-CFR Navigation Aids

Browse

Simple Search

Advanced Search

 — Boolean

 — Proximity

 

Search History

Search Tips

Corrections

Latest Updates

User Info

FAQs

Agency List

Incorporation By Reference

eCFR logo

Related Resources

Electronic Code of Federal Regulations

e-CFR data is current as of July 1, 2020

Title 29Subtitle BChapter XVIIPart 1926Subpart S → Appendix


Title 29: Labor
PART 1926—SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION
Subpart S—Underground Construction, Caissons, Cofferdams and Compressed Air


Appendix A to Subpart S of Part 1926—Decompression Tables

1. Explanation. The decompression tables are computed for working chamber pressures from 0 to 14 pounds, and from 14 to 50 pounds per square inch gauge inclusive by 2-pound increments and for exposure times for each pressure extending from one-half to over 8 hours inclusive. Decompressions will be conducted by two or more stages with a maximum of four stages, the latter for a working chamber pressure of 40 pounds per square inch gauge or over.

Stage 1 consists of a reduction in ambient pressure ranging from 10 to a maximum of 16 pounds per square inch, but in no instance will the pressure be reduced below 4 pounds at the end of stage 1. This reduction in pressure in stage 1 will always take place at a rate not greater than 5 pounds per minute.

Further reduction in pressure will take place during stage 2 and subsequent stages as required at a slower rate, but in no event at a rate greater than 1 pound per minute.

Decompression Table No. 1 indicates in the body of the table the total decompression time in minutes for various combinations of working chamber pressure and exposure time.

Decompression Table No. 2 indicates for the same various combinations of working chamber pressure and exposure time the following:

a. The number of stages required;

b. The reduction in pressure and the terminal pressure for each required stage;

c. The time in minutes through which the reduction in pressure is accomplished for each required stage;

d. The pressure reduction rate in minutes per pound for each required stage;

Important Note: The Pressure Reduction in Each Stage is Accomplished at a Uniform Rate. Do Not Interpolate Between Values Shown on the Tables. Use the Next Higher Value of Working Chamber Pressure or Exposure Time Should the Actual Working Chamber Pressure or the Actual Exposure Time, Respectively, Fall Between Those for Which Calculated Values Are Shown in the Body of the Tables.

ExamplesMinutes
Example No. 1: 4 hours working period at 20 pounds gauge.
Decompression Table No. 1: 20 pounds for 4 hours, total decompression time43
Decompression Table No. 2:
Stage 1: Reduce pressure from 20 pounds to 4 pounds at the uniform rate of 5 pounds per minute.
Elapsed time stage 1: 16/53
Stage 2 (final stage): Reduce pressure at a uniform rate from 4 pounds to 0-pound gage over a period of 40 minutes.
Rate—0.10 pound per minute or 10 minutes per pound.
Stage 2 (final) elapsed time40
Total time43
Example No. 2: 5-hour working period at 24 pounds gage.
Decompression Table No. 1: 24 pounds for 5 hours, total decompression time117
Decompression Table No. 2:
Stage 1: Reduce pressure from 24 pounds to 8 pounds at the uniform rate of 5 pounds per minute.
Elapsed time stage 1: 16/53
Stage 2: Reduce pressure at a uniform rate from 8 pounds to 4 pounds over a period of 4 minutes. Rate, 1 pound per minute elapsed time, stage 24
Transfer men to special decompression chamber maintaining the 4-pound pressure during the transfer operation.
Stage 3 (final stage): In the special decompression chamber, reduce the pressure at a uniform rate from 4 pounds to 0-pound gage over a period of 110 minutes. Rate, 0.037 pound per minute or 27.5 minutes per pound. Stage 3 (final) elapsed time110
Total time117

Decompression Table No. 1—Total Decompression Time

Work pressure p.s.i.g.Working period hours
12 1112 2345678Over 8
9 to 1233333333333
1466666666161633
167777771733484862
18777811174863637387
20778151543637383103113
22991624386893103113128133
24111223275292117122127137151
261314293469104126141142142163
281523314198127143153153165183
3017283862105143165168178188204
3219354385126163178193203213226
3421395898151178195218223233248
36244463113170198223233243253273
38284973128178203223238253263278
40314984143183213233248258278288
423756102144189215245260263268293
444364118154199234254264269269293
464474139171214244269274289299318
485189144189229269299309319319
505894164209249279309329

Decompression Table No. 2

[Do not interpolate, use next higher value for conditions not computed]

Working chamber pressure p.s.i.g.Working period hoursDecompression data
Stage No.Pressure reduc. p.s.i.g.Time in stage minutesPressure reduc. rate Min/poundTotal time decompress minutes
FromTo
14 12 114420.206
      24041.006
   1114420.206
      24041.006
   112 114420.206
      24041.006
   2114420.206
      24041.006
   3114420.206
      24041.006
   4114020.206
      24041.006
   5114420.206
      24041.006
   6114420.20
      24041.006
   7114420.20
      240143.5016
   8114420.20
      240143.5016
   Over 8114420.20
      240307.5032
16 12 116430.20
      24041.007
   1116430.207
      24041.007
   112 116430.20
      24041.007
   2116430.20
      24041.007
   3116430.20
      24041.007
   4114430.20
      24041.007
   5114430.207
      24043.5017
   6114430.20
      240307.5033
   7114430.20
      2404511.2548
   8114430.20
      2404511.2548
   Over 8114430.20
      2406015.0063
18 12 118430.20
      24041.007
   1118430.20
      24041.007
   112 118430.20
      24041.007
   2118430.20
      24051.258
   3118430.20
      24082.0011
   4118430.20
      240143.5017
   5118430.20
      2404511.2548
   6118430.20
      2406015.0063
   7118430.20
      2406015.0063
   8118430.20
      2407017.5073
   Over 8118430.20
      2408421.0087
20 12 120430.20
      24041.007
   1120430.20
      24041.007
   112 120430.20
      24051.258
   2120430.20
      240123.0015
   3120430.20
      240123.0015
   4120430.20
      2404010.0043
   5120430.20
      2406015.0063
   6120430.20
      2407017.5073
   7120430.20
      2408020.0083
   8120430.20
      24010025.00103
   Over 8120430.20
      24011027.50113
22 12 122630.20
      26061.009
   1122630.20
      26061.009
   112 122630.20
      260132.2016
   2122630.20
      260213.5024
   3122630.20
      260355.8538
   4122630.20
      2606510.8368
   5122630.20
      2609015.0093
   6122630.20
      24010016.67103
   7122630.20
      26011018.35113
   8122630.20
      26012520.80128
   Over 8122630.20
      26013021.70133
24 12 124830.20
      28441.00
      34041.0011
   1124830.20
      28441.00
      34051.2512
   112 124830.20
      28441.00
      340164.0023
   2124830.20
      28441.00
      340205.0027
   3124830.20
      28441.00
      3404511.2552
   4124830.20
      28441.00
      3408521.2592
   5124830.20
      28441.00
      34011027.50117
   6124830.20
      28441.00
      34011528.80122
   7124830.20
      28441.00
      34012030.00127
   8124830.20
      28441.00
      34013032.50137
   Over 8124830.20
      28482.00
      34014035.00151
26 12 1261030.20
      210461.00
      34041.0013
   11261030.20
      210461.00
      34051.2514
   112 1261030.20
      210461.00
      340205.0029
   21261030.20
      210461.00
      340256.2534
   31261030.20
      210461.00
      3406015.0069
   41261030.20
      210461.00
      3409523.75104
   51261030.20
      210481.33
      34011528.80126
   61261030.20
      210481.33
      34013032.50141
   71261032.20
      210491.50
      34013032.50142
   81261030.20
      210491.50
      34013032.50142
   Over 81261030.20
      2104305.00
      3403032.50163
28 12 1281230.20
      212481.00
      34041.0015
   11281230.20
      212481.00
      340123.0023
   112 1281230.20
      212481.00
      340205.0031
   21281230.20
      212481.00
      340307.5041
   31281230.20
      2124101.25
      3408521.2098
   41281230.20
      2124141.75
      34011027.50127
   51281230.20
      2124202.50
      34012030.00143
   61281230.20
      2124202.50
      34013032.50153
   71281230.20
      2124202.50
      34012032.50153
   81281230.20
      2124324.00
      34013032.50165
   Over 81281230.20
      2124506.25
      34013032.50183
30 12 1301430.20
      2144101.00
      34041.0017
   11301430.20
      2144101.00
      340153.7528
   112 1301430.20
      2144101.00
      340256.2538
   21301430.20
      2144141.40
      3404511.2562
   31301430.20
      2144171.70
      3408521.20105
   41301430.20
      2144303.00
      34011027.50143
   51301430.20
      2144353.50
      34013032.50165
   61301430.20
      2144353.50
      34013032.50168
   71301430.20
      2144454.50
      34013032.50178
   81301430.20
      2144555.50
      34013032.50188
   Over 81301430.20
      2144717.10
      34013032.50204
32 12 1321630.20
      2164121.00
      34041.0019
   11321630.20
      2164121.00
      340205.0035
   112 1321630.20
      2164151.25
      340256.2543
   21321630.20
      2164221.83
      3406015.0085
   31321630.20
      2164282.33
      3409523.75126
   41321630.20
      2164403.33
      34012030.00163
   51321630.20
      2164453.75
      34013032.50178
   61321630.20
      2164605.00
      34013032.50193
   71321630.20
      2164705.83
      34013032.50203
   81321630.20
      2164806.67
      34013032.50213
   Over 81321630.20
      2164937.75
      34013032.50226
34 12 1341830.20
      2184141.00
      34041.0021
   11341830.20
      2184141.00
      340225.5039
   112 1341830.20
      2184251.80
      340307.5058
   21341830.20
      2184352.50
      3406015.0098
   31341830.20
      2184433.10
      34010526.25151
   41341830.20
      2184553.93
      34012030.00178
   51341830.20
      2184624.43
      34013032.50195
   61341830.20
      2184856.07
      34013032.50218
   71341830.20
      2184906.43
      34013032.50223
   81341830.20
      21841007.15
      34013032.50233
   Over 81341830.20
      21841158.23
      34013032.50248
36 12 1362030.20
      2204161.00
      34051.2524
   11362030.20
      2204161.00
      340256.2544
   112 1362030.20
      2204301.88
      340307.5063
   21362030.20
      2204402.50
      3407017.50113
   31362030.20
      2204523.25
      34011528.75170
   41362030.20
      2204654.06
      34013032.50198
   51362030.20
      2204905.63
      34013032.50223
   61362030.20
      22041006.25
      34013032.50233
   71362030.20
      22041106.88
      34013032.50243
   81362030.20
      22041207.50
      34013032.50253
   Over 81362030.20
      22041408.75
      34013032.50273
38 12 1382230.20
      2226161.00
      36091.5028
   11382230.20
      2226161.00
      360305.0049
   112 1382230.20
      2226201.25
      360508.3473
   21382230.20
      2226301.88
      3609515.83128
   31382230.20
      2226352.19
      36014023.35178
   41382230.20
      2226503.12
      36015025.00203
   51382230.20
      2226553.44
      36016527.50223
   61382230.20
      2226704.38
      36016527.50238
   71382230.20
      2226855.32
      36016527.50253
   81382230.20
      2226955.93
      36016527.50263
   Over 81382230.20
      22261106.88
      36016527.50278
40 12 1402430.20
      2248161.00
      38441.00
      44082.0031
   11402430.20
      2248161.00
      38451.25
      440256.2549
   112 1402430.20
      2248161.00
      384205.00
      4404511.2584
   22402430.20
      1248251.56
      384205.00
      4409523.75143
   31402430.20
      2248301.88
      384307.50
      44012030.00183
   41402430.20
      2248452.81
      384358.75
      44013032.50213
   51402430.20
      2248472.94
      3845313.25
      44013032.50233
   61402430.20
      2248553.44
      3846015.00
      44013032.50248
   71402430.20
      2248654.06
      3846015.00
      44013032.50258
   81402430.20
      2248754.70
      3846015.00
      44013032.50268
   Over 81402430.20
      2248955.93
      3846015.00
      44013032.50288
42 12 1422630.20
      22610161.00
      310461.00
      440123.0037
   11422630.20
      22610161.00
      3104122.00
      440256.2556
   112 1422630.20
      22610161.00
      3104233.83
      4406015.00102
   21422630.20
      22610161.00
      3104305.00
      4409523.75144
   31422630.20
      22610161.00
      3104508.34
      44012030.00189
   41422630.20
      22610171.06
      31046510.83
      44013032.50215
   51422630.20
      22610271.69
      31048514.18
      44013032.50245
   61422630.20
      22610271.69
      310410016.67
      44013032.50260
   71422630.20
      22610301.88
      310410016.67
      44013032.50263
   81422630.20
      22610352.19
      310410016.67
      44013032.50268
   Over 81422630.20
      22610603.75
      310410016.67
      44013032.50293
44 12 1442830.20
      22812161.00
      312481.00
      440164.0043
   11442830.20
      22812161.00
      3124202.50
      440256.2564
   112 1442830.20
      22812161.00
      3124273.38
      4407218.00118
   21442830.20
      22812161.00
      3124405.00
      4409523.75154
   31442830.20
      22812161.00
      3124607.50
      44012030.00199
   41442830.20
      22812161.00
      31248510.62
      44013032.50234
   51442830.20
      22812161.00
      312410513.13
      44013032.50254
   61442830.20
      22812161.00
      312411514.38
      44013032.50264
   71442830.20
      22812161.00
      312412015.00
      44013032.50269
   81442830.20
      22812161.00
      312412015.00
      44013032.50269
   Over 81442830.20
      22812402.50
      312412015.00
      44013032.50293
46 12 1463030.20
      23014161.00
      3144101.00
      440153.7544
   11463030.20
      23014161.00
      3144252.50
      440307.5074
   112 1463030.20
      23014161.00
      3144353.50
      4408521.20139
   21463030.20
      23014161.00
      3144474.70
      44010526.25171
   31463030.20
      23014161.00
      3144656.50
      44013032.50214
   41463030.20
      23014161.00
      3144959.50
      44013032.50244
   51463030.20
      23014161.00
      314412012.00
      44013032.50269
   61463030.20
      23014161.00
      314412512.50
      44013032.50274
   71463030.20
      23414161.00
      310414014.00
      44013032.50289
   81463030.20
      23014161.00
      314415015.00
      44013032.50299
   Over 81463030.20
      23014251.56
      314416016.00
      44013032.50318
48 12 1483230.20
      23216161.00
      3164121.00
      440205.0051
   11483230.20
      23216161.00
      3164352.92
      440358.7589
   112 1483230.20
      23216161.00
      3164453.75
      4408020.00144
   21483230.20
      23216161.00
      3164605.00
      44011027.50189
   31483230.20
      23216161.00
      3164907.50
      44012030.00229
   41483230.20
      23216161.00
      316412010.00
      44013032.50269
   51483230.20
      23216161.00
      316414011.67
      44013032.50209
   61483230.20
      23216161.00
      316416013.33
      44013032.50309
   71483230.20
      23216161.00
      316417014.17
      44013032.50
   81483230.20
      23216161.00
      316417014.17
      44013032.50
50 12 1503430.20
      23418161.00
      3184141.00
      440256.2558
   11503430.20
      23418161.00
      3184402.86
      440358.7594
   112 1503430.20
      23418161.00
      3184553.93
      4409022.50164
   21503430.20
      23418161.00
      3184705.00
      44012030.00209
   31503430.20
      23418161.00
      31841007.15
      44013032.50249
   41503430.20
      23418161.00
      31841308.58
      44013032.50279
   51503430.20
      23418161.00
      318416011.42

Decompression Table No. 2—Continued

[Do not interpolate, use next higher value for conditions not computed]

Working chamber pressure p.s.i.g.Working period hoursDecompression data
Stage No.Pressure reduc. p.s.i.g.Time in stage minutesPressure reduc. rate Min/poundTotal time decompress minutes
FromTo
      44013032.50309
   61503430.20
   23418161.00
   318418012.85
      44013032.50329

[44 FR 8577, Feb. 9, 1979; 44 FR 20940, Apr. 6, 1979, as amended at 58 FR 35311, June 30, 1993]

Need assistance?