(a) General.
(1) All wells or shafts over 5 feet in depth
into which employees are permitted to enter shall be retained with lagging,
spiling, or casing.
EXCEPTION: Exploration shafts; see Section
1542(d).
(2) The lagging, spiling or casing shall
extend at least one foot above ground level and shall be provided the full
depth of the shaft or at least five feet into solid rock if possible.
(3) All wells, pits, shafts, caissons, etc.
shall be barricaded or securely covered.
(4) Upon completion of exploration and
similar operations, temporary wells, pits, shafts, etc., shall be
backfilled.
(b) Small
Shafts in Hard Compact Soil.
Two-inch (nominal) cribbing may be used in square shafts
not over 4 feet square in hard compact soil. Each member shall be cut ½
way through the width of the member and dovetailed into position so each member
will act as a shore as well as lagging. Strips shall be nailed in each corner
to prevent the boards from dropping down.
(c) Shafts in Other Than Hard Compact Soil.
(1) A system of lagging supported by braces
and corner posts shall be used for square or rectangular shafts. Corner posts
of 4-inch by 4-inch material are normally acceptable in shafts 4 feet square,
or smaller, if they are braced in each direction with horizontal 4-inch by
4-inch members at intervals not exceeding 4 feet. Braces and corner posts in
larger shafts shall be correspondingly larger as determined by a civil
engineer.
(2) Round shafts shall be
completely lagged with 2-inch material which is supported at intervals not
greater than 4 feet by means of adjustable rings of metal or timber that are
designed to resist the collapsing force, or cased in a manner that provides
equivalent protection.
(d) Exploration Shafts. Only a geotechnical
specialist shall be permitted to enter an exploration shaft without lagging,
spiling or casing for the purpose of subsurface investigations under the
following conditions:
(1) Initial Inspection.
The type of materials and stability characteristics of the exploration shaft
shall be personally observed and recorded by the geotechnical specialist during
the drilling operation. Potentially unsafe exploration shafts shall not be
entered.
(2) Surface Casing. The
upper portion of the exploration shaft shall be equipped with a surface
ring-collar to provide casing support of the material within the upper 4 feet
of the exploration shaft. The ring-collar shall extend at least 1-foot above
the ground surface.
(3) Gas Tests.
Prior to entry into exploration shafts, tests and/or procedures shall be
instituted to assure that the atmosphere within the shaft does not contain
dangerous air contamination or oxygen deficiency. These tests and/or procedures
shall be maintained while working within the shaft to assure that dangerous air
contamination or oxygen deficiency will not occur. (See Section
5156 of the General Industry Safety
Orders.)
(4) Unstable Local
Conditions. The geotechnical specialist shall not descend below any portion of
any exploration shaft where caving or groundwater seepage is noted or
suspected.
(5) Ladder and Cable
Descents. A ladder may be used to inspect exploration shafts 20 feet or less in
depth. In deeper exploration shafts, properly maintained mechanical hoisting
devices with a safety factor of at least 6 shall be provided and used. Such
devices shall be under positive control of the operator being positive powered
up and down with fail-safe brakes.
(6) Emergency Standby Employee. An emergency
standby employee shall be positioned at the surface near the exploration shaft
opening whenever a geotechnical specialist is inside the shaft.
(7) Communication. A two-way,
electrically-operated communication system shall be in operation between the
standby employee and the geotechnical specialist whenever boring inspections
are being made in exploration shafts over 20 feet in depth or when ambient
noise levels make communication difficult.
(8) Safety Equipment. The following safety
equipment shall be used to protect the geotechnical specialist:
(A) An approved safety harness which will
suspend a person upright and that is securely attached to the hoist
cable.
(B) A 12-inch to 18-inch
diameter steel coneshaped headguard/deflector that is attached to the hoist
cable above the harness.
(C) A
hoist cable having a minimum diameter of 5/16 inches.
(D) Approved head protection. (See Section
1515.)
(9) Electrical Devices. All electrical
devices used within the exploration shaft by the geotechnical specialist shall
be approved for hazardous locations.
(10) Surface Hazards. The storage and use of
flammable or other dangerous materials shall be controlled at the surface to
prevent them from entering the exploration shaft.
Notes
Cal. Code Regs. Tit. 8, §
1542
1.
Amendment of subsection (e) filed 5-21-75; effective thirtieth day thereafter
(Register 75, No. 21).
2. Amendment filed 8-23-82; effective
thirtieth day thereafter (Register 82, No. 35).
3. Amendment of
subsection (a) and new subsection (e) filed 11-12-82; effective thirtieth day
thereafter (Register 82, No. 46).
4. Repealer of subsection (a)
NOTE, adoption of subsections (a)(3) and (a)(4), repealer of subsection (d)
text and relettering filed 8-26-91; operative 9-25-91 (Register 92, No.
13).
5. Change without regulatory effect amending subsection (a)(1)
filed 8-19-92; operative 8-19-92 (Register 92, No. 34).
6. Editorial
correction of printing error restoring designation of subsection (d) (Register
92, No. 34).
7. Change without regulatory effect amending subsection
(a)(1) Exception filed 2-22-93; operative 3-24-93 pursuant to title 1, section
100, California Code of Regulations
(Register 93, No. 9).
Note: Authority cited: Section
142.3, Labor
Code. Reference: Section
142.3, Labor
Code.
1. Amendment of
subsection (e) filed 5-21-75; effective thirtieth day thereafter (Register 75,
No. 21).
2. Amendment filed 8-23-82; effective thirtieth day
thereafter (Register 82, No. 35).
3. Amendment of subsection (a) and
new subsection (e) filed 11-12-82; effective thirtieth day thereafter (Register
82, No. 46).
4. Repealer of subsection (a) NOTE, adoption of
subsections (a)(3) and (a)(4), repealer of subsection (d) text and relettering
filed 8-26-91; operative 9-25-91 (Register 92, No. 13).
5. Change
without regulatory effect amending subsection (a)(1) filed 8-19-92; operative
8-19-92 (Register 92, No. 34).
6. Editorial correction of printing
error restoring designation of subsection (d) (Register 92, No.
34).
7. Change without regulatory effect amending subsection (a)(1)
Exception filed 2-22-93; operative 3-24-93 pursuant to title 1, section 100,
California Code of Regulations (Register 93, No. 9).