Page 221 - Water Engineering Hydraulics, Distribution and Treatment

Gate N
Gauge B
Gate M
To private
From public
3
/ 4 ˝ test
system
water main
Gauge A
drain D
3
/ 4 ˝ test drain E
Check valve G
Check valve F
Steel foothold inserts
Brick or concrete pit
Plan Gauge C 6.8 Management, Operation, and Maintenance of Distribution Systems 199
Indicator post
optional
Manhole
Wood cover
Steel foothold
inserts
Gauge A
Figure 6.17 Cross-connection between
Gauge B Gauge C municipal water supply and private
Blowoff
(industrial) water supply protected by
Sleeve Spacer 3–5 ft long double check-valve installation. To test
F G installation: (1) close gates M and N; (2)
open test drain B, and observe gauges A
3 / 4 ˝ test
Cast-iron M D 3 / 4 ˝ test drain E N Cast-iron and B; (3) open test drain E, and observe
pipe drain pipe gauge C. If check valves F and G are
tight, gauge A will drop to zero; gauges
Siphon ejector or drain B and C will drop slightly owing to
Floor pitched to drain
compression of rubber gaskets on check
Concrete support
valves F and G. Conversion factors:
Section 1 = 1in. = 25.4 mm; 1 ft = 0.3048 m.
′′
meter pit was buried in the ground and the top of the pit work alone at job sites, the area should first be evaluated and
was at ground level. A metal cap was attached to the rim of all possible hazards identified and addressed by supervisory
the water meter pit and a water meter with an in-line shutoff personnel. The location of the water valve inside the water
valve. A screw handle water valve and the municipal water meter pit required the use of extension tools, thereby elimi-
line were located in the pit. The valves were approximately nating the need to enter the water meter pit (even partially).
36 in. (914 mm) below the top of the pit (or ground level).
The victim removed the metal cap covering the pit and placed
6.8.2 Plumber Repairing a Water Line Killed
the cap on the ground next to the pit opening. He then knelt
When Struck by a Backhoe Bucket
beside the opening on both knees and reached into the pit
until his head, both arms, and part of his shoulders were A 47-year-old male plumber died when he was struck by the
inside the water meter pit. Apparently, the victim became bucket of a backhoe while he was repairing a water line in
stuck upside down in the opening and could not free himself, a trench for a shopping center. The victim and an apprentice
causing asphyxiation due to positional deprivation of air. plumber were at the bottom of the trench removing straight
Recommendation #1: Supervisory personnel should and angled cast-iron pipes and placing them in the backhoe
routinely monitor employee performance to determine if bucket. The operator of the backhoe was an employee of the
employees have impaired physical and mental capabilities, shopping center. The operator told the police investigator that
which may be related to the use of alcohol, illegal or over- when he released all controls, the bucket swerved to the left
the-counter drugs, or prescription medications. striking the victim on his left side and pinning him against
Recommendation #2: Supervisory personnel should the trench wall.
identify, evaluate, and address all possible hazards asso- A trench had to be excavated to reach the pipe. The
ciated with the job site. When employees are expected to trench was an oblong shape measuring approximately 31 ft