Guidelines for Excavation Work Done Near Our Underground ...
Transcript of Guidelines for Excavation Work Done Near Our Underground ...
Guidelines for Excavation Work Done Near Our Underground Infrastructures
April 2020 - Version 1
Information Regarding the Publication
This is the first edition of the Guidelines for Excavation Work Done Near Underground Infrastructures.The updated digital version is available on Info-Excavation’s website at info-ex.com.These new guidelines replace the older versions of guidelines from collaborating owners of underground infrastructures.Printed copies of these new guidelines are also available at [email protected].
Important:Important: BEFORE starting excavation work, a locate request must be made to Info-Excavation at info-ex.com, or if it’s an emergency please call 1 800 663-9228If underground infrastructures are located within your work area, all responses and locate reports must be received and in hand before undertaking any excavation work.
3Guidelines for Excavation Work Done Near Our Underground Infrastructures
Introduction The guidelines are intended for anyone that is either planning an excavation project or excavating near underground infrastructures. They state which regulations must be followed, and specify the general technical requirements prescribed by the network owners collaborating in this document. This document’s goal is to properly anticipate the activities, delays and costs involved in meeting these requirements. However, the job’s design as well as the choice of working methods and practices used to comply with these requirements are the sole responsibility of those performing the work.
This document has been created to ensure public safety and the safety of workers, prevent damages to underground infrastructures and maintain essential services. These are the priorities set forth by Info-Excavation and its partners.
Excavation and ground disturbance work must be made in accordance with legislation applicable to this type of work, such as legislation relating to occupational health and safety and any regulation made within such legislation, particularly those concerning construction projects.
It remains the responsibility of those planning the excavation project or performing the excavation work near underground infrastructures to respect and enforce compliance with applicable laws, regulations and standards which supersede this document.
Anyone doing excavation work must receive all proper approvals (municipal, MTQ, private landowners, etc.) and locate reports, and keep them on the worksite.
For underground infrastructures regulated by the Canada Energy Regulator (CER), please refer to the “Damage Prevention” section of the CER’s website to learn about applicable regulations.
4 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Excavation and ground disturbance work may include, but are not limited to, the following:
a) Digging;b) Excavating;c) Trenching;d) Ditching;e) Tunnelling;f ) Trenchless excavation/drilling/pile-driving;g) Drill and tap/hydraulic jacking;h) Stripping of topsoil;i) Profiling/levelling;j) Plowing for the installation of an underground infrastructure;k) Planting trees;l) Land clearing and stump removal (grubbing);m) Blasting/use of explosives;n) Concrete and asphalt crushing and scarring;o) Installing fence posts, guardrail posts, rods, anchors or stakes;p) Pipelines or other major underground infrastructures crossing underneath
the travelled portion of a public road;q) Underwater excavating work.
Worker Training
Info-Excavation offers free training on damage prevention to underground infrastructures and many owners of underground infrastructures offer specific training related to their underground network, keeping employees informed on which best practices to use and the risks to public safety and the safety of workers.
5Guidelines for Excavation Work Done Near Our Underground Infrastructures
List of Collaborating Owners of Underground Infrastructures Natural Gas
• 1-844-780-4355• Authorization request and servitude management:
1-866-630-3450 or [email protected]
• 1-819-771-8321, option 1 (emergency)• Engineering Department: [email protected]
Electricity
• 514-868-3111 (CSEM - Network Maintenance Division)• Outside regular business hours:
call 311 or 514-809-3390
1-800-790-2424
Telecommunication
• Quebec: • Damage Prevention Management:
1-877-255-2325, option 3• Damage Reporting:
1-877-255-2355, options 2 - 4• Engineering Department:
[email protected] or call 1-877-247-5888• Atlantic Provinces: 1-844-224-8344• Ontario: 1-844-225-5550• Alberta: 1-800-242-3447• British Columbia: 1-800-474-6886• Manitoba: 1-800-940-3447
514-380-5555 or 1-833-688-5555
• Quebec:• Damage Reporting:
1-888-434-2425• Engineering Department:
1-866-935-2473 / [email protected]
This document was developed by the network owners listed above and in collaboration with Info-Excavation.
6 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Table of ContentsIntroduction 3
45
7
Worker Training List of Collaborating Owners of Underground Infrastructures
In Case of an Emergency or Damage
1- Project Planning 111.1 Engineering Request 111.2 Clearance to be Respected Depending on Type of Work 11
1.2.1 Planting Trees and Shrubs 111.2.2 Ditch Grading/Cleaning Works 121.2.3 Trenchless Excavation 12
1.2.3.1 Drilling Parallel to an Underground Infrastructure 121.2.3.2 Vertical Drilling (coring, pile-driving, etc.) 131.2.3.3 Drilling Perpendicular to an Underground Infrastructure 13
1.2.4 Installing a New Underground Infrastructure 141.2.5 Specific Requirements for Natural Gas 151.2.6 Help for Project Planning 16
1.3 Observations Made of Future Work Areas 171.4 Depth of Underground Infrastructures 171.5 Consequences of Your Work on Different Networks 171.6 Minimum Covering Requirements 17
2- Before Work Begins 182.1 Locate Request 182.2 Locate Report 182.3 Survey Excavations 182.4 Confined Areas (Manhole or Shafts) 192.5 Overload, Traffic and Structures Above the Buffer Zone 20
3- During Excavation Work 223.1 Maintaining Markers 223.2 Soft Excavation 233.3 Using a Concrete Saw (Surface Sawing) 243.4 Requirements Near a Buffer Zone 243.5 Support 253.6 Backfilling 27
3.6.1 Unshrinkable Backfill 293.6.2 Compaction 30
3.7 Unlocated Infrastructures or Inaccurate Location 303.8 Blasting, Dynamic Compaction and Pile-Driving 313.9 Axial Force Points 33
References 34Glossary 35
In C
ase
of a
n E
mer
gen
cy o
r D
amag
e
2 - Non-explosion-proof equipment: Unprotected equipment that could ignite vapours, dust or gas because of the sparks or heat it generates.
Natural Gas: Damage causing a gas leak
• Avoid flames and sparks (cigarettes, cell phones and any other non-explosion-proof equipment2).
• Move rapidly away from the leak.
• If the natural gas ignites:• Do not attempt to put out the flames.• Remain at a safe distance from the fire.• Wait for the arrival of the fire department.
Telecommunication:
There are three types of telecommunication cable: copper wire, coaxial cable and fibre-optic lines. Each of these has its own hazards.
• Never handle a damaged fibre-optic line or look directly at the fibre’s end. Fibre-optic lines transmit light that may damage the retina permanently and are covered by a hard-metal jacket that may be sharp and very dangerous.
• Do not touch or move copper wires or coaxial cables, as they may transmit an important electrical current and their hard-metal jacket may be very sharp and dangerous. However, if handling is necessary, always wear leather protective gloves.
Stop working.
Leave the equipment in place, shut off heavy machinery engines and all other motorized or electrical equipment.
Do not attempt to repair, backfill or seal off the damage.
In an emergency, call 911.
➔➔
➔
➔
7
In Case of an Emergency or Damage:
In C
ase
of a
n E
mer
gen
cy o
r D
amag
e
For any other situation or damage such as gaps, grooves, abrasions, dents, cracks made on an underground infrastructure or any other damage made to connected equipment (tracer wires, lines, anodes, etc.), please notify the owner of the damaged infrastructure or Info-Excavation, and verify the written instructions given in the locate reports. Consult the list of owners of underground infrastructures collaborating in this document.
• NEVER leave a trench exposed in a way that makes it accessible to the public. All necessary safeguards must be installed.
• NEVER bury a damaged infrastructure, whatever the extent of damages.
• If you discover that a natural gas pipeline has ruptured a sewer line, communicate immediately with customer service of the owner of the underground infrastructure.
Electricity:
Heavy Equipment Operator:
• Stay calm. Stay in the vehicle and don’t touch any metal parts inside the vehicle.
• If possible, call 911 or emergency services. Mention that electrical equipment has been damaged.
• If a bystander wants to help you, tell them not to approach the vehicle and, above all, not to touch it.
• If you are inside the vehicle, but in imminent danger:
• Put your feet together and keep your arms close to your body.
• Keep your feet together as you jump out. Make sure you never touch any metal part of the vehicle and the ground at the same time.
• Hop away from the vehicle, keeping your feet together until you are at least 10 metres away from the vehicle or from any fallen power lines.
Workers near Fallen Power Lines (less than 10 metres):
• If possible, call 911 or emergency services. Mention that an electrical equipment has been damaged.
• Do not approach the vehicle and do not touch it. Tell anyone in the vicinity to stay well away from the vehicle and not to touch it.
• Hop away from the vehicle, keeping your feet together until you are at least 10 metres away from the vehicle or from any fallen power lines
In Case of an Emergency or Damage:
8
Project Planning
Proj
ect P
lann
ing
10 Guidelines for Excavation Work Done Near Our Underground Infrastructures
1 - Project Planning 1.1 Engineering Request
Once a project reaches the planning or bidding stage it is critical to check if any underground infrastructure is located near your worksite in order to:
• Avoid any unforeseen costs or delays during the work;• Plan for all the precautionary measures needed;• Warn those involved of the risk of incidents.
You need to make an engineering request to Info-Excavation to access plans from owner members of underground infrastructures, and find out which underground infrastructures are located within your work area. Allow five (5) business days to receive the plan.
Please note that information regarding any data transmitted may vary from one company to another. In the event a plan cannot be transmitted by the owner member of the underground infrastructure, markers could be made.
Making an engineering request shall under no circumstances exempt you from making a locate request before starting the excavation work.
You must contact owners of underground infrastructures directly if they are not members of Info-Excavation (such as some municipalities and RCM’s). For the complete list of members, please visit Info-Excavation’s website.
1.2 Clearance to be Respected Depending on Type of Work
1.2.1 Planting Trees and Shrubs
A minimum clearance distance is required between the existing underground infrastructure and the planted tree or shrub (e.g., Énergir and Gazifère require 1.2 m (4 ft) between the root ball and the wall of the underground infrastructure). The clearance distance may differ depending on the nature of the underground infrastructure. For some owners of underground infrastructures, these requirements will be specified on locate reports and in the “Overall Clearance” table (see Section 1.2.6).
For underground infrastructures located within concrete duct banks, the minimum clearance distance is 1.0 m (3 ft). For important underground infrastructures (e.g., high-pressure natural gas pipelines, vital pipelines, etc.) identified by a specific reference in the locate report, an authorization request must be submitted and the owner of the relevant underground infrastructure will require a larger lateral clearance for trees and shrubs.
When it is impossible to respect the recommended clearance, an agreement must be reached with the owner of the underground infrastructure. Please consult the list of owners of underground infrastructures collaborating in this document.
Project Planning
11Guidelines for Excavation Work Done Near Our Underground Infrastructures
Project Planning
1.2.2 Ditch Grading/Cleaning Works
A locate request is required for this type of work. Each owner of underground infrastructures will state the instructions to be followed.
Instructions set forth by owners of underground infrastructures are important, as there are specific risks related to ditch grading and cleaning. For instance, the owner may require that a company representative be onsite while work is performed.
1.2.3 Trenchless Excavation
For work done using drilling equipment, the risk of damaging the infrastructure is enhanced. Conditions to be respected are outlined in the following paragraphs. Clearance distance may vary depending on the nature of the underground infrastructure. Instructions can be written on locate reports as well as in the “Minimum Clearance Distance” table, Section 1.2.6 (e.g., Hydro-Québec and TransÉnergie 1.5 m [5 ft]; Bell 2 m [6.6 ft]).
1.2.3.1 Drilling Parallel to an Underground Infrastructure
No drilling can be done at a distance of less than 1.2 m (4 ft) from landmarks (markers or sketches) provided by the owner of the underground infrastructure. In some cases, however, this zone may be extended. You are responsible for complying with this clearance distance (see the “Minimum Clearance Distance” table, Section 1.2.6. and notes on locate reports).
Figure 1 - Drilling Parallel to an Underground Infrastructure
DirectionalDrilling
SurveyExcavations
Underground Infrastructure Located and Marked
Survey Excavations
Directional Drilling
Receiver
Transmitter
Receiver
Transmitter
Underground Infrastructure Located and Marked Soft or Manual
Excavation
Zone Cleared
Markers
Markers
Prohibited Trenchless Excavation Zone
10 m max.
1 m min.
300 m min.
1 m min.
12 Guidelines for Excavation Work Done Near Our Underground Infrastructures
1.2.3.1 Drilling Parallel to an Underground Infrastructure (cont’d)
When the trenchless excavation path runs alongside an underground infrastructure at a distance between 1.2 m (4 ft) and 3 m (10 ft) from landmarks, survey excavations must be dug at intervals not exceeding 10 m (32 ft) along the trenchless excavation path so that the precise location of the drilling head and back reamers (if any) can be checked visually. The width of these survey excavations must be sufficient to be able to see the entire width of the drilling equipment from entry point to exit point along its entire length.
If there are crossings along the trenchless excavation path, please refer to the “Drilling Perpendicular to an Underground Infrastructure” 1.2.3.3 section.
1.2.3.2 Vertical Drilling (coring, pile-driving, etc.)
Drilling must be done at a minimum clearance distance of 1.2 m (4 ft) from landmarks (markers or sketches) provided by the owner of the underground infrastructure.
In some cases, however, this zone may be extended. You are responsible for complying with this clearance distance. Please refer to the “Minimum Clearance Distance” table shown in Section 1.2.6. and to the notes on locate reports.
Table 1 - Specific Requirements for Énergir and Gazifère
Distance between survey excavations depending on the type of drilling and the distance from the infrastructure
Distance Between Well Torpedo Path and Natural Gas Pipeline (m)
Distance Between Survey Excavations (m)
Directionnal Drilling from 1.2 to 3 10
“Torpedo” Drilling Type
Less than 1.6 Forbidden*
1.6 6.5
1.7 7.0
1.8 7.5
1.9 8.0
2.0 8.5
2.1 9.0
2.2 9.5
from 2.3 à 3 10.0
* No drilling using such equipment as a well torpedo is allowed at a distance of less than 1.6 m from a natural gas pipeline
Project Planning
13Guidelines for Excavation Work Done Near Our Underground Infrastructures
Project Planning
DirectionalDrilling
SurveyExcavations
Underground Infrastructure Located and Marked
Survey Excavations
Directional Drilling
Receiver
Transmitter
Receiver
Transmitter
Underground Infrastructure Located and Marked Soft or Manual
Excavation
Zone Cleared
Markers
Markers
Prohibited Trenchless Excavation Zone
10 m max.
1 m min.
300 m min.
1 m min.
Figure 2 - Perpendicular Drilling Over an Underground Infrastructure
1.2.3.3 Drilling Perpendicular to an Underground Infrastructure
When the drilling path crosses an underground infrastructure, the infrastructure must first be completely cleared. The width of the survey excavation must be sufficient (as per Figure 2) enough to be able to see the entire width of the drilling equipment, and to allow for the interruption of the drilling operation before any contact with the infrastructure is made or if an anomaly is detected.
Drilling must be done at a minimum clearance distance of 300 mm from the existing underground infrastructure (see Table 2 - Clearances to Maintain for Some Owners of Underground Infrastructures in section 1.2.6 and the notes in the locate reports).
The underground infrastructure must be adequately supported to maintain its original depth throughout the drilling operation so as to avoid damaging the underground infrastructure, while avoiding it shifting either horizontally or vertically at any point or at any time. Please consult Section 3.5 “Support” to ensure the protection of exposed underground infrastructures.
1.2.4 Installing a New Underground Infrastructure
Clearance instructions must be complied with when installing any other infrastructure. When it is impossible to respect these distances, special measures can be considered. In such situations, it is your responsibility to communicate with the owner of the underground infrastructure (consult the list of owners of underground infrastructures collaborating in this document) to propose an alternative solution, which is subject to his approval.
For important underground infrastructures (e.g., high-pressure natural gas pipelines, vital pipelines, etc.) identified by a specific reference in the locate report, the contractor must communicate with the infrastructure’s owner to know the required clearance distance.
14 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Bu�er Zone(minimum)
Parallel to Underground Infrastructures
Perpendicular to Underground Infrastructures
Bu�er Zone(minimum)
Bu�er Zone(minimum)
Bu�er Zone(minimum)
Parallel to Underground Infrastructures
Perpendicular to Underground Infrastructures
Bu�er Zone(minimum)
Bu�er Zone(minimum)
Figure 3 - Parallel Structures Figure 4 - Perpendicular Structures
1.2.4 Installing a New Underground Infrastructure (cont’d)
• Work Parallel to an Underground Infrastructure (see Figure 3)Any structure installation that is parallel to existing underground infrastructures must be located at least 1 m (3 ft) from them to facilitate any future intervention. This distance may vary depending on the underground infrastructure. Please refer to the “Minimum Clearance Distance” table shown in Section 1.2.6.
• Work Crossing an Underground Infrastructure (see Figure 4)Any structure installation that crosses existing underground infrastructures must be located at least 300 mm (12 in) from them. It is preferable to maximize this distance. This distance may vary depending on the underground infrastructure. Please refer to the “Minimum Clearance Distance” table shown in Section 1.2.6.
• Infrastructures Giving Off HeatFor infrastructures that give off heat near existing underground infrastructures, the clearance distance may vary from one owner to the next. Please contact the owner to learn what guidelines must be followed.
For safety purposes related to potential gas migration after a leak, the natural gas pipeline must be kept above any other type of facility. Please contact the owner of the underground infrastructure if you cannot comply with this requirement.
1.2.5 Specific Requirements for Énergir and Gazifère
If your project (e.g., excavation, heavy equipment, etc.) is within an Énergir servitude or within 3.0 m of a Gazifère vital main (VM), a written authorization must be received from the owner of the underground infrastructure before you begin excavating. These specific requirements will be specified in locate reports.
Project Planning
15Guidelines for Excavation Work Done Near Our Underground Infrastructures
Project Planning
1.2.6 Help for Project Planning - March 2020 Version
1 - Fo
r net
work
s loc
ated
with
in a
serv
itude
, an
auth
oriza
tion
requ
est i
s req
uire
d (se
e the
list
of th
e su
bjec
ted
owne
rs).
2 - Fo
r tre
nchl
ess e
xcav
atio
n us
ing
well
torp
edos
, se
e Tab
le 1,
Sect
ion
1.2.
3.1.
Tab
le 2
- C
lear
ance
s to
Mai
nta
in fo
r So
me
Ow
ner
s o
f Un
der
gro
un
d In
fras
tru
ctu
res
Typ
e o
f Un
der
gro
un
d In
fras
tru
ctu
reN
atu
ral G
as
Ele
ctri
city
Oth
er
Ow
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f Un
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gro
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fras
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erg
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Tra
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CS
EM
Typ
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f Net
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Dist
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700k
Pa o
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-Pre
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feed
10
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290
0 kP
a
Very
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Tran
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Vita
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or M
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than
44
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High
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4kV
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Wri
tten
au
tho
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tio
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it
(10
bu
sin
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day
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e re
qu
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o1
No
1Ye
sN
oN
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sN
oN
oN
/A
Sup
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req
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uri
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exc
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wo
rk
(req
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es a
48
-ho
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no
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req
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dit
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ho
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sN
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/A
Min
imu
m C
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ran
ce R
eq
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1.2
.1 T
ree
Pla
nti
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1.2
m (4
ft)
1.2
m (4
ft)
Auth
oriza
tion
requ
est
requ
ired
1.2
m (4
ft)
1.2
m (4
ft)
2.5
m (8
ft)
1.5
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ft)
31
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1.2
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1.2
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3 m
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1.2
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1.5
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1.2
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4
Perp
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30
0 m
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30
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m (1
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Auth
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30
0 m
m (1
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60
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3 m
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60
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30
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30
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60
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60
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30
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Requ
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Red
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Per
mit
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30
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m (2
ft)
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00
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t)3
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ft)
4
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stin
g, D
ynam
ic C
om
pac
tio
n
30
m (1
00
ft)
30
m (1
00
ft)
60
m (2
00
ft)
30
m (1
00
ft)
30
m (1
00
ft)
60
m
(20
0 f
t)3
0 m
(10
0 f
t)3
0 m
(10
0 f
t)3
0 m
(1
00
ft)
4
3.8
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-Dri
vin
g1
0 m
(33
ft)
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m (3
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t)3
0 m
(10
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t)3
0 m
(10
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t)3
0 m
(10
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(2
00
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4
For c
lear
ance
dist
ance
s tha
t mus
t be c
ompl
ied w
ith fo
r inf
rastr
uctu
res o
wned
by
Bel
l, Tel
us an
d Vid
éotro
n, th
e own
ers r
efer
to th
e CSA
22.3
stan
dard
, not
e 7
“Und
ergr
ound
Infra
struc
ture
s” as
wel
l as t
o CER
IU’s
guid
elin
es re
lated
to th
e “e
xten
sion
of u
nder
grou
nd lin
es” a
nd to
“bes
t pra
ctice
s for
mak
ing
trenc
hes”.
3 - Sp
ecifi
cs fo
r Hyd
ro-Q
uébe
c: Th
e cle
aran
ce d
istan
ces m
entio
ned
mus
t be
take
n fro
m th
e cen
tre of
the t
ree/
shru
b to
th
e lan
dmar
ks (m
arke
rsor s
ketc
hes).
4 - Sp
ecifi
cs of
CSEM
: The
clea
ranc
e di
stanc
e men
tione
d m
ust b
e tak
en fr
om
theu
nder
grou
nd in
frastr
uctu
re’s
oute
r wal
l.
5 - Fo
r tre
nchl
ess e
xcav
atio
n an
d ex
cava
tion
work
only.
This table is a summary. For information related to details and specifics, please consult the different sections of this document.
16 Guidelines for Excavation Work Done Near Our Underground Infrastructures
1.3 Observations Made of Future Work Areas
At the planning stage, visit the future worksite to ensure that the answers received from the owners of underground infrastructures match what is observed onsite. Among other things, observe:
• Markers of underground infrastructures;• Posts (electrical and telecommunication signs);• Underground structures or housings.
In the event of any inconsistency, please contact Info-Excavation or the owner of the underground infrastructure.
1.4 Depth of Underground Infrastructures
Never assume that you know the depth of an underground infrastructure. The depth (also called cover) of underground infrastructures varies depending on the location, even over short distances. It may be determined by survey excavations (also called test cuts or exploratory cuts) done using soft excavation methods. A locate request is required before doing survey excavations.
Depending on the nature of the work planned, it may be necessary to ascertain the depth when planning operations in order to avoid any setbacks.
1.5 Consequences of Your Work on Different Networks
It is important that you communicate with the owners of underground infrastructures in the early stages of planning a project that includes, for example, modifying the use or profile of land, or installing or moving underground or aboveground infrastructures.
It’s important to maintain access to underground infrastructures and to comply to the requirements of owners of underground infrastructures. Permanent structures are prohibited above underground infrastructures.
The nature and scope of the work planned may call for putting specific safety measures in place and may sometimes involve supporting, moving or replacing existing installations. Specific information is described under Section 1.2 “Clearance to Be Respected Depending on Type of Work”. Please consult the list of owners of underground infrastructures collaborating in this document.
1.6 Minimum Covering Requirements
The thickness and the nature of the final covering for underground infrastructures must always be restored to their original levels and comply with the minimum requirements of owners of underground infrastructures. They must also comply with the requirements ofthe municipality or those of Transports Québec for lands that belong to themor that fall under their jurisdiction when their thickness requirements are higherthan those shown.
Project Planning
Before Work Begins
Befo
re W
ork
Begi
ns
18 Guidelines for Excavation Work Done Near Our Underground Infrastructures
2 - Before Work Begins2.1 Locate Request
Before undertaking any type of ground disturbance or excavation work, no matter how deep it is, you must first:
• Make a locate request to Info-Excavation (through info-ex.com or on their mobile application (IOS and Android) — Free service 24/7;
• Have a valid locate report at all times.
2.2 Locate Report
All answers and locate reports must be received from owners of underground infrastructures located in the work area. It is particularly important to:
• Be aware of instructions specified in the locate report and guidelines established by owners of underground infrastructures;
• Ensure that the work zone identified in the sketch included with the locate request match the locate reports received.
• Ensure that the location of the infrastructures (markers, stakes, flags or any other method used for locating) and the work zone match the work to be undertaken.
• Pay close attention to the data identified in locate reports and ensure they match the markers, if applicable.In the event of any inconsistency, contact the owner of the relevant underground infrastructure or Info-Excavation.
• Ensure that every worker within the excavation area understands the information provided in locate reports.
• Keep all relevant documents (paper or electronic) onsite throughout the excavation. Keep an extra copy in the excavating equipment (excavator).
2.3 Survey Excavations3
Survey excavations allow to physically locate an underground infrastructure marked within the work area. They must be done using recognized soft excavation methods, and executed within the buffer zone. Verify the specifics for each owner of underground infrastructures under the “Soft Excavation” section.
3 - Survey excavations, investigative digging or test cuts — consult the videos on these methods (info-ex.com/dvd).
Before Work Begins
19Guidelines for Excavation Work Done Near Our Underground Infrastructures
Before Work Begins
2.4 Confined Areas (Manhole or Shafts)
• Confined area covers must not be removed except for the special instructions given below.
• Access request for confined areas: An access request must be made to the owners of underground infrastructures. Except for the specific requirements related to sidewalk repairs, please consult the list of owners of underground infrastructures collaborating in this document.
Specific Requirements of Certain Owners of Underground Infrastructures:
CSEM:Specific guidelines for sidewalk rehabilitation. For sidewalk rehabilitation, only highly skilled and trained individuals for work in confined areas are authorized to open access wells without making an authorization request.
Without entering them, they can visually determine the distance between the sidewalk slab and the top of the access well. These individuals are required to inspect, properly verify them and take all necessary precautions to prevent personal injury or damages linked to gas accumulation within these confined areas. This visual inspection is mandatory before sawing the sidewalk slabs since the top of certain access wells serve as sidewalks.
Telus and Vidéotron:Specific guidelines for all confined areas. Only highly skilled and trained individuals for work in confined areas are authorized to open access wells without making an authorization request.
Without entering them, these individuals are required to inspect, properly verify them and take all necessary precautions to prevent personal injury or damages linked to gas accumulation within these confined areas.
20 Guidelines for Excavation Work Done Near Our Underground Infrastructures
2.5 Overload, Traffic and Structures Above the Buffer Zone
Working methods must ensure the integrity of underground infrastructures. The frequent use and high volume of heavy equipment may undermine the integrity of underground infrastructures and even lead to damage. When using heavy equipment, a locate request must be made prior to its use to determine the location of underground infrastructures.
Specific Requirements of Certain Owners of Underground Infrastructures:
Bell, Telus, Vidéotron and Hydro-Québec:An authorization request must be sent to owners of underground infrastructures prior to using any heavy equipment.
It is forbidden to:• Place heavy equipment over existing underground structures;• Use vibrating equipment (e.g., jackhammer) near these structures;• Use heavy equipment over infrastructures.
Énergir and Gazifère:An authorization request must be sent to owners of underground infrastructures prior to any heavy equipment crossing over underground structures when there is no pavement or when land levelling is done.
Parking heavy equipment within the buffer zone is forbidden (e.g., a crane including its stabilizers).
No structure (temporary or permanent) or any storage (materials, containers, trailers, etc.) are authorized within the buffer zone.
Before Work Begins
During Excavation Work
Dur
ing
Exca
vatio
n W
ork
22 Guidelines for Excavation Work Done Near Our Underground Infrastructures
3 - During Excavation WorkDuring excavation work near underground infrastructures, preventive measures, such as supporting structures, are necessary to ensure their integrity and protect them from all possible forms of deterioration (e.g., vandalism, drop of materials, road accidents, etc.). Infrastructures and related equipment must never be used as a step, resting area or anchorage point.Employees of owners of underground infrastructures are the only ones having the ability to inspect the condition of damaged infrastructures and perform the required repairs.
The integrity of the ground on which infrastructures stand must be maintained throughout the excavation. Infrastructures should not be laid within an unstable slope zone, which in turn relies upon the nature and level of soil saturation and upon nearby traffic loads. When required, access to shoring structures or an engineering design study must be available.
Do not rely solely on the warning tape, as it is not always present (this varies depending on the region and the installation method used initially when the underground infrastructure was built).
3.1 Maintaining Markers
The principal contractor is responsible for taking all necessary measures to maintain markers of underground infrastructures. In situations where there is a risk that markers disappear during evacuation work (e.g., when the paving surface is being removed) the visual location markers provided by the owner of the underground infrastructure are used to redo the markers.
Markers must comply with the North American standardized colour code used to identify the different types of underground infrastructures.
RED
Electricity
ORANGE
Telecommunication & Cables
BLUE
Waterworks
WHITE
Pre-marking
YELLOW
Natural gas & Hydrocarbon
GREEN
Sewers
PINK
Survey
PURPLE
Irrigation
During Excavation Work
23Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
3.2 Soft Excavation
Soft excavation methods include manual digging, vacuum excavation techniques, aero excavation and hydro excavation. The method for excavating must be adapted to ensure that the structural integrity of the underground infrastructure is maintained.
Only soft excavation is authorized within the buffer zone until the exact location of the underground infrastructure is verified visually.
• Only a competent, qualified and trained worker must operate the hydro-excavation equipment.
• A spinning tip nozzle is the preferred equipment used for hydro-excavation. However, its use is mandatory for Énergir and Gazifère.The maximum water pressure to be used during the excavation differs from one owner to the next. When many underground infrastructures are located within the work area, the strictest instructions must be respected.
• Pressure measurements must be constantly monitored using a calibrating device mounted on the hydro-excavator (truck, pump) or on the wand in order to avoid damaging the underground infrastructure.
• The wand must never remain motionless during an excavation. Always avoid aiming directly at the underground Infrastructure.
• Maintain a minimum distance of 20 cm (8 in) between the nozzle end of the wand and the underground infrastructure or the bottom of the excavation. Never insert the nozzle into the bottom of the excavation when excavating above an underground infrastructure.
• The end fitting of the suction hose must be made of a non-metallic, supple material that will not damage the underground infrastructure.
• The wand must be fitted with a device capable of stopping the excavation on demand, such as an automatic trigger or a safety valve.
• The water temperature must never exceed 45 °C (115 °F).
Specific Requirements of Owners of Underground Infrastructures:
Bell, CSEM, Hydro-Québec, Telus and Vidéotron: 10 350 kPa (1,500 lb/in2).
Énergir, Gazifère, CSEM and Hydro-Québec: 17 250 kPa (2,500 lb/in2).
24 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Specific Requirements of Certain Owners of Underground Infrastructures:
CSEM: Structures may be used as sidewalk slabs or pavement. Make sure you know their thickness before sawing. To verify the structure’s thickness, please consult the “Confined Areas” section and the CSEM’s specific requirements..
Bell, Vidéotron and Telus: Saw cuts must be done outside the buffer zone. Using soft excavation methods, the contractor may then excavate toward the markers made within the work area to determine the location and depth of underground infrastructures.
Infrastructure
Bu�erzone Bu�erzone
Figure 5 - Mechanical Excavation Prohibited Within the Buffer Zone
3.3 Using a Concrete Saw (Surface Sawing)
Pay close attention to markers located above underground infrastructures, since the depth of underground infrastructures may vary, even along short distances.
The depth cut must be adjusted according to the type of ground covering so as not to exceed its thickness during the cut.
3.4 Requirements Near a Buffer Zone
Mechanical excavation is not allowed within the buffer zone until the exact location of the underground infrastructure is verified visually using soft excavation methods. A clearance table is available for some infrastructure owners in section 1.2.6.
Mechanical excavation is permitted directly above the pipeline for removing the solid portion of the surface covering (e.g., asphalt, concrete, sidewalk, etc.). No mechanical excavation is permitted deeper than the paving surface.
Once the underground infrastructure is visually located, the work manager is authorized to use mechanical equipment closer to the infrastructure, within its immediate location, and according to specific requirements made by each owner of an infrastructure and the nature of the underground infrastructure.
Only a soft excavation method is authorized near the infrastructure so as to maintain the structural integrity of the infrastructure.
During Excavation Work
25Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
Énergir: The maximum distance between supports must meet the following requirements (see exemple in Figure 6 and 7):
Diameter of Natural Gas Pipeline Maximum Distance Between 2 Supports
168 mm (6 in) or less 3 m (10 ft)
More than 168 mm (6 in) 5 m (16 ft)
The gas underground infrastructures must be supported by a smooth support having a width equal to at least half the diameter of the pipeline and bearing one third of its circumference, as shown in Figure 6.
Specific Requirements of Certain Owners of Underground Infrastructures:
Bell, CSEM, Hydro-Québec, Telus and Vidéotron: Plans and methods of support must be signed and sealed by an engineer. This falls under the principal contractor’s responsibility.
If you have any questions, please contact the owner of the underground infrastructure. Consult the list of owners of underground infrastructures participating in this document.
3.5 Support
The underground infrastructure must be adequately supported to maintain its original depth throughout the project in order to avoid damaging it and to keep it from shifting either horizontally or vertically at any point or at any time. (The use of chains is not permitted as a supporting method.)
Even if made of concrete, no underground infrastructure is self-supporting.
Underground infrastructures must be supported by a smooth support as shown in Figure 6. The underground infrastructure may also rest directly on the supports (as shown in Figure 7), provided that they do not damage the underground infrastructure itself or its coating. To achieve this, materials such as rubber or wood are required.
When the structure is a concrete duct bank, the load calculation must be made in connection with the supporting plan shown to the owner of the underground infrastructure. The webbing used and its strength’s specifications must comply with the supporting plan based on the weight of the structure. Plank lumber must be installed under the structure’s corners to distribute the pulling force and avoid damaging the concrete duct bank’s coating.
Where underground infrastructures are inserted in a cast iron, steel or plastic casing, special precautions may be necessary. When needed, communicate with the owner of the underground infrastructure.
26 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Dimensions of Supporting Beam and Maximum Reach Between Supporting Beams
Nominal Pipe Size (NPS) Steel Polyethylene
2 4.5 2 4.5
½ à 2 S.O. 4 X 6 4 X 6 4 X 6
3 à 6 S.O. S.O. 4 X 4 6 X 6
The beam must be category 1 S-P-F (spruce, pine, fir) or equivalent. If the beam’s reach exceeds 4.5 m (15 ft), a continuous wooden beam may not be available; if so, I-steel beams (or their equivalent) may be used. The chosen steel beams must be certified by a professional engineer (see exemple in Figure 6 and 7).
Maximum Distance
(See table)
Infrastructure
Steel beam
120°minimum
Infrastructure
Maximum Distance
(See table)
Infrastructure
Figure 6 - Overhead Support (Exemple for Énergir et Gazifère).
Figure 7 - Underlying Support (Exemple for Énergir et Gazifère).
Maximum Distance
(See table)
Infrastructure
Steel beam
120°minimum
Infrastructure
Specific Requirements of Certain Owners of Underground Infrastructures (cont’d):
Gazifère:For the maximum reach without a supporting beam, the instructions to be followed are detailed in this table (see exemple in Figure 6 and 7):
Nominal Pipe Size (NPS) Steel m (ft) Polyethylene m (ft)
½ 2 (6.6) 1 (3.3)
¾ to 1¼ 2.5 (8.2) 1.25 (4.1)
2 3 (10) 1.5 (5)
3 to 4 4.5 (15) 1.75 (6)
6 6 (20) 2 (6.6)
8 7 (23) 2 (6.6)
During Excavation Work
27Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
3.6 Backfilling
Backfilling must be undertaken using great care by avoiding, among other things, the use of sharp objects, compacted or frozen soil, and by not burying pipe ends or other waste.
If conditions permit, the use of excavated soils or material should be preferred when backfilling to minimize the impact of winter frost (trench heaving or trench depression). Mineral and compactible materials must be used. Organic soils (branches, stumps, etc.), contaminated materials, rocks and clumps of frozen earth whose diameter exceeds 150 mm must be removed.
When reusing materials that are in place proves to be impossible, use clean backfilling materials or new granulates from a sand pit or quarry site that meet the requirements of these two tables:
*Bedding: Backfilling must provide support under the underground infrastructure when excavation work is deeper than the underground infrastructure. Always use unshrinkable backfill as bedding material under concrete duct banks.
**Covering: To avoid damaging the coating on underground infrastructures when they are non-concrete, the backfill material (covering around the infrastructure) must meet the granulometric requirements shown in Tables 3 and 4.
Table 3 - Granulometric Requirements of Bedding* and Covering** Material
Sieve
20 mm 5 mm 80 μm
% PASSING 100 90 - 100 0 -10
Table 4 - Approved Granulates
Type of Granulates Classification Note
Backfill and Covering Materials
BC 80 μm - 5 mm NQ 2560-114
Concrete sand 0 - 5 mm
Manufactured sand 0 - 5 mm
Crushed gravel 0 - 5 mm
Granitic sand 0 - 5 mm
Other granulates approved by the laboratory
28 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Warningtape
Back�llingMaterial
CoveringMaterial
UndergroundInfrastructure
Between 300 and 400 mm from the surface of the ground(or directly above the coveringmaterial in the case ofunshrinkable backfill)
150 mm min. above the pipelineIn the case of unshrinkable backfill, 300 mm min. of covering materialis required.
150 mm min. from each side of the underground infrastructure
100 mm below the underground infrastructure
Warning Tape
CoveringMatérial
UndergroundInfrastructure
350 mm
300 mm unshrinkable back�llmaterial bedding.
Figure 8 - Non-Concrete Underground Infrastructure
Figure 9 - Concrete Underground Infrastructure
Note: For Gazifère, the warning tape is not always present.
3.6 Backfilling (cont’d)
Backfilling must comply with the following figures:
During Excavation Work
29Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
Table 5 - Characteristics of Unshrinkable Backfill:
Resistance 28 days (MPa) 0.4 to 0.8
Quantity of Cement (kg/m3) 25
Type of Cement GU and/or GUb
Maximum Diameter for Coarse Granulates (mm) 20
Quantity of Fine Granulates, Including Cement (% Passing 80 µm) ≤ 3,5
4 - This guideline must comply with the 13101 standard, Tome VII — MTQ Material..
3.6 Backfilling (cont’d)
• When excavation work is done under a concrete duct bank within less than 300 mm from it, the use of unshrinkable backfill material should be given priority to ensure adequate compaction of the underground infrastructure (see Figure 9). When this is impossible, appropriate granulates must be used.
• Never leave sharp or pointy materials near underground infrastructures, as they may eventually damage the covering or the exterior coat and damage the infrastructures.
• Backfilling must be done without using tamping equipment directly on exposed installations.
• Water found at the bottom of a trench may hinder backfilling and compaction operations. Pumping must be used to withdraw water.
• A geotextile4 must be laid at the bottom of the excavation when its bottom is easily liquefiable and reworkable. If a geotextile is already there, it should be repaired or repositioned.
• For important underground infrastructures (e.g., very high-pressure natural gas pipelines, vital pipelines) specified in the locate report, an authorization request must be submitted since the required backfill material must be specifically validated in every case.
3.6.1 Unshrinkable Backfill
This self-compacting material is mainly used in areas where compaction is difficult. This material is not recommended for thicknesses of less than 300 mm.The unshrinkable backfill must come from a certified BNQ supplier as set out in protocol NQ 2621 9001 12. Fine and coarse granulates must comply with the CAN/CSA-A23.1/A23.2 13 standard. No air-entraining admixture must be used in unshrinkable backfill. Characteristics of unshrinkable backfill are as follows:
30 Guidelines for Excavation Work Done Near Our Underground Infrastructures
3.6.2 Compaction
Compaction of the trench’s backfilling material is critical to limit residual compaction.
Compaction of backfill material must be done in successive layers with a maximum thickness of 300 mm and the compaction method varies depending on the thickness of the backfill material and equipment used.
3.7 Unlocated Infrastructures or Inaccurate Location
Never assume an unlocated infrastructure is abandoned and that it is safe.
Should you come across an unlocated infrastructure, cease work immediately and contact Info-Excavation without delay. When necessary, the locator working for the owner of the underground infrastructure will be sent to the site.
An inaccurate location must also be reported to Info-Excavation or directly to the owner of the underground infrastructure.
Specific Requirements of Certain Owners of Underground Infrastructures:
Énergir and Gazifère:No compaction equipment must be used until the backfill above the natural gas pipeline and connections (e.g., service line tee) has reached a depth of 300 mm (12 in).
Only manual or light compaction equipment (e.g., manual vibrating plate, handheld tamper) may be used for depths between 300 mm and 600 mm (12 in and 24 in). Also, refrain from driving over the pipeline to avoid subjecting it to excessive stress.
Once there is more than 600 mm (24 in) of backfill material that is compacted, heavy compaction equipment (e.g., roller) may be used up to the final level.
During Excavation Work
31Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
5 - Safety Code for the Construction Industry S-2.1, r.4, Act Respecting Explosives, RLRQ, c. E-22,Regulation Under the Act Respecting Explosives (LRQ, c. E-22, r. 1).
Specific Requirements of Certain Owners of Underground Infrastructures:
Bell and Vidéotron:An authorization request, prepared and signed by a specialist must be transmitted for review to the owner of the underground infrastructure concerned at least thirty (30) business days before work begins to allow him to comment on vibration waves that may reach underground infrastructure.Underground and surrounding aerial infrastructures must be identified and protected.For their contact information, please consult the list of owners of underground infrastructures collaborating in this document. The following items must be included in your authorization request:
• Name of the contractor and principal contractor (worksite manager);
• Expected work date;
• Construction plan showing the worksite location and the location of underground infrastructures (Info-Excavation);
• Description of the blasting, dynamic compaction or pile-driving techniques to be used, including safety measures for the general public and workers;
• Calculations of vibrations (anticipated speed and amplitude on telecommunication underground infrastructures based on their construction specifications) sealed by an engineer;
3.8 Blasting, Dynamic Compaction and Pile-Driving
The use of one of these techniques near underground infrastructures must be done with great care since they generate vibrations that are likely to impact the integrity of those infrastructures.
Underground infrastructures cannot be exposed before blasting. If exposing the infrastructure is inevitable, the contractor must take all necessary precautions to protect the exposed underground infrastructure against projectiles. Blasting (anti-shrapnel) mats must be used to minimize the risk of projectiles.The contractor must comply with Québec’s standardized specifications5 over and above the blasting requirements of the owner of the underground infrastructure.
32 Guidelines for Excavation Work Done Near Our Underground Infrastructures
Specific Requirements of Certain Owners of Underground Infrastructures:
Énergir and Gazifère:An authorization request, prepared and signed by a specialist must be transmitted to the owner of the given underground infrastructure for review at least ten (10) business days before work begins for all blasting, dynamic compaction or pile-driving work done within 60 metres of natural gas underground infrastructures.
Énergir Gazifère DistanceAuthorization
Request Required
Blasting or Dynamic Compaction
Very High-Pressure Transmission
Over 2900 kPa
High-Pressure and Extra
High-Pressure Network
< 60 m Yes
Natural Gas andDistribution and
High-Pressure 2900 kPa and less
All Conduits < 30 m Yes
Pile-Driving
Very High-Pressure Transmission
Over 2900 kPa
High-Pressure and Extra
High-Pressure Network
< 30 m Yes
Natural Gas andDistribution and
High-Pressure 2900 kPa and less
All Conduits < 10 m Yesi
The following items must be included in your authorization request:
• Name of the contractor and principal contractor (worksite manager);
• Expected work date;
• A construction plan showing the worksite location and the location of any natural gas pipelines (Info-Excavation);
• Description of the blasting, dynamic compaction or pile-driving techniques to be used, including safety measures for the general public and workers;
• Calculations of vibrations (anticipated speed and amplitude on natural gas pipelines) sealed by an engineer;
• Method for measuring vibrations during the work (e.g., location of seismographs to confirm the calculations);
• Declaration stating that the daily seismographic results will be sent to the technical personnel concerned within 24 hours following the work;
• Declaration indicating that any seismographic result that exceeds the vibration limits described below will lead to immediate work interruption, which will last until the authorization from the distributor is received.
3.8 Blasting, Dynamic Compaction and Pile-Driving (cont’d)
During Excavation Work
33Guidelines for Excavation Work Done Near Our Underground Infrastructures
During Excavation Work
For blasting, dynamic compacting and pile-diving, the maximum limits of vibration and amplitude are as follows:
Type of WorkMaximum limits of
vibration and amplitude speed
Vibration Amplitude
Blasting 50 mm/s 0.15 mm
Dynamic Compaction and Pile-Driving 50 mm/s 0.4 mm
Specific Requirements of Certain Owners of Underground Infrastructures:
Gazifère: Additional precautions must be taken when working near axial force points. Axial force points occur on pipeline connections such as elbow connections (45 or 90°), end caps, welding tees, reducers, restricted flow valves, and partially or completely closed valves. Axial force points may also occur during operational activities such as closing a valve to isolate a main pipeline, lowering a pipeline obturator to isolate a main pipeline, clamp or block by crushing a main pipeline in an emergency. Should excavation work expose an axial force point or an area near an axial force point, specific instructions provided by the gas distributor and written on the locate report must be followed. Failure to follow these guidelines could result in serious injuries or property damage.
3.8 Blasting, Dynamic Compaction and Pile-Driving (cont’d)
3.9 Axial Force Points
34 Guidelines for Excavation Work Done Near Our Underground Infrastructures
References Regulations
• Natural Gas: All applicable legislation related to work done near gas networks, such as those mentioned in Chapter II, (Gas) of the Construction Code L.R.Q., c. B-1,1, r. 2), in Chapter III (Gas) of the Safety Code (L.R.Q., c. B-1,1, r. 3) and in the Safety Code for the Construction Industry (L.R.Q., c. S-2,1, r. 6) takes precedence.
• Electricity: All legislation and applicable standards related to work done near electrical networks, including those in the Safety Code for the Construction Industry (LRQ, c S-2.1, r 4) take precedence.
• Act Respecting Occupational Health and Safety (L.R.Q., c. S -2.1)
• Safety Code for the Construction Industry (c. S -2.1, r. 4)
Guides and Useful Links
• “Protection of Underground Infrastructures. Best Practices” Version 3.0 — October 2019, from the CCGA (Canadian Common Ground Alliance).
• “Guide des bonnes pratiques pour la réalisation de tranchées” from the CERIU (Centre d’expertise et de recherche en infrastructures urbaines).
• “Guide sur le prolongement de lignes souterraines en milieu urbain” from the CERIU.
References
35Guidelines for Excavation Work Done Near Our Underground Infrastructures
Glossary:Buffer Zone: An area defined by the owner of the underground infrastructure within which excavation work using mechanical equipment cannot be carried out until the underground infrastructure is exposed by safe methods such as soft excavation like manual digging or vacuum excavation.
Confined Area: Means any area that is completely or partially enclosed, is not designed for human occupation, nor intended to be, but may occasionally be occupied for the performance of work. Access can only be had by a restricted entrance/exit. It can represent a risk for the health and safety of anyone who enters.(Reference: Act Respecting Occupational Health and Safety (RSST, art. 1)
Contractor*: A person who carries out construction work or has construction work carried out, or makes or submits a bid for someone else (either personally or by an intermediary) for the purpose of carrying out such work or having it carried out for financial gain.
Gazifère’s Vital Mains (VM): • Vital mains are gas pipelines that are considered critical components in the
distribution system’s operations and for supplying gas to many key customers. They fall under the jurisdiction of the CER and the pipeline Integrity Management Program (IMP).
• An interruption of or damage to the infeed of these systems could negatively impact Gazifère’s operations as well as public safety and the safety of workers.
Overload: Heavy equipment (e.g., Dump trucks, backhoes, power shovels, quarry or forestry trucks, crawler drills, cranes, etc.) and any vehicle the MTQ considers non-standard (MTQ CI-625).
Tamping: Action of filling the trench and packing the material in one movement, by taping it using the bucket. The correct way is to place the material in the trench, which must then be compacted by successive layers.
For other questions related to definitions, please consult the Guide to Best Practices under Annex A Glossary, available on Info-Excavation’s website at info-ex.com/damage prevention/guides and tools.
Glossaire
* This definition does not, in any way, exclude any person who carries out ground disturbance work as described in the Introduction section of these guidelines
This document was developed by the owners of underground infrastructures appearing on the cover page and in collaboration with Info-Excavation.
The updated digital version is available on Info-Excavation’s website at info-ex.com.
Stop working.
Leave the equipment in place, shut off heavy machinery engines and turn off all other motorized or electrical equipment.
Do not attempt to repair, backfill or seal off the damage.
In an emergency, call 911.
➔
➔
➔
➔
In Case of an Emergency or Damage: