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DTE ENERGY’s BEST PRACTICES FOR
GEOSPATIAL DATA COLLECTIONAdolfo Castillo, P.S.
Professional Surveyor
January 12, 2015
A look at DTE Energy’s Geospatial Data
Collection safety practices on new
underground utility installations within
MDOT’s R.O.W.s’
3
4.1
Ft
> 2 Ft
Open cut excavation – Anatomy of a Gas explosion
Existing Gas Main
New Gas Main
Gas mainSlow leak
?
?
Commercial
Buildings
MDOT’s R.O.W.
MD
OT
’s R
.O.W
.
Shopping PlazaShopping Plaza
A
A
LEGENDNew Utility Installation
Exposed steel gas main
Buried steel gas main
Open Cut Excavation
Strong GPS Reception/Signal
Unconfined gas following the path of least resistance
Open cut excavation – Gas explosion
Deflection Points
Deflection Points
100 Ft. interval Typ.
Terminus Point
Cross Section View
4
Leaking gas main
GPS Rover
5
Temperature within a single spark equals 5,000 ° F to 8,000 ° F common voltage,
amperage and medium (gas/air) vary to 1,000,000 ° F
Facts
The actual temperature of a lit cigarette = 752° F or 400z
Highest temperature of a lit cigarette (At draw) = 1292 ° F or 700 ° C.
The Auto ignition Temperature of a standard unleaded gasoline varies from 475 ° F to 536 ° F or 246 ° C to 480 ° C
The Auto ignition Temperature of Methane (Natural Gas) = 1076 ° F or 580 ° C
Source of information: The Engineering Tool Box, and Physics and Astronomy Online.
6
9 F
t
Existing installation
New installation
Open cut excavation – Anatomy of a trench cave-in
1’
?
?
Commercial
Buildings
MDOT’s R.O.W.
MD
OT
’s R
.O.W
.
Shopping PlazaShopping Plaza
B
Open cut excavation – Earth wall collapse
Deflection Points
Deflection Points
Terminus Point
Cross Section View
7
B
< 1
’
> 2
’ > 2
’
Utility Installation
Open Cut Excavation
Strong GPS
Reception/Signal
Excavation Spoil
GPS Rover
LEGEND
8
MORE FACTS
From 2004 through 2013, the U.S. had:
• 286 trench cave-in incidents. 163 fatalities. 10 of the 286 cave-in incidents occurred in Michigan, 9 of them fatal.
• 745 serious incidents with gas distribution, causing 278 fatalities and 1059 injuries, with $110,658,083 in property damage.
• 110 serious incidents with gas transmission, resulting in 41 fatalities, 195 injuries, and $448,900,333 in property damage.
Data source: United States Department of Labor. OSHA Fatality and Catastrophe Investigation Summaries
Open cut excavation with Trench Box
6 Ft
9F
t
Existing installation
New installation
Trench Box
Open cut excavation with Hydraulic Bracing
6 Ft
9F
t
Existing installation
New installation
Hydraulic Braces
Steel Sheeting
Steel Sheeting
11
13.5’
9 F
t
Existing installation
New installation
4Ft
1’
1.5’
Open cut excavation with Sloped Side-Walls
• Trenches 20 feet (6.1 meters) deep or greater require that the protective system be designed by
a registered professional engineer or be based on tabulated data prepared and/or approved by a
registered professional engineer in accordance with 1926.652(b) and (c).
• OSHA standards require safe access and egress to all excavations, including ladders, steps,
ramps, or other safe means of exit for employees working in trench excavations 4 feet (1.22
meters) or deeper. These devices must be located within 25 feet (7.6 meters) of all workers.
.
.
.
• Keep heavy equipment away from trench edges.
• Trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is
made entirely in stable rock. If less than 5 feet deep, a competent person may determine that a
protective system is not required.
Rules for working in and near excavations
Data source: United States Department of Labor. OSHA Trenching and Excavation Safety
.
.
.
• Identify other sources that might affect trench stability.
• Keep excavated soil (spoils) and other materials at least 2 feet (0.6 meters) from trench edges.
• Know where underground utilities are located before digging.
• Test for atmospheric hazards such as low oxygen, hazardous fumes and toxic gases when > 4 feet
deep.
• Inspect trenches at the start of each shift
Rules for working in and near excavations
Data source: United States Department of Labor. OSHA Trenching and Excavation Safety
.
.
.
• Inspect trenches following a rainstorm or other water intrusion
• Do not work under suspended or raised loads and materials.
• Inspect trenches after any occurrence that could have changed conditions in the trench.
• Ensure that personnel wear high visibility or other suitable clothing when exposed to
vehicular traffic.
Rules for working in and near excavations
Data source: United States Department of Labor. OSHA Trenching and Excavation Safety
Questions ?
Comments?
Gracias
Thank you for your attention to this presentation, and for your participation.
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