This document outlines a health and safety risk assessment for trial trench excavations, identified hazards, and control measures to mitigate risks associated with working near live underground services. It emphasizes pre-work checks, communication of service locations, and adherence to safety protocols for excavation and equipment use. Additional measures for weather conditions and worker exposure to heat are also detailed, ensuring compliance with relevant regulations and standards.

1. HEALTH SAFETY AND ENVIRONMENT Author: Approved:
RISK ASSESSMENT: 09 TRIAL TRENCHES (HAND DIGGING) TO MAS STANDARD
Issued: Rev. Date:
Revision: 0
Page 1 of 2 HSEQ -Rev-01(Jan-2023)
No
Specific Task Step
(In sequence of
works)
Hazard Details Consequence/Risk
Initial Risk
Rating Control Measures Residual Risks
Additional Control
Measures
RR
P S RR
1
Planned shallow
Excavation (Trial
Trench) in areas where
live services may be
present including:
 Electrical;
 Water;
 Sewerage;
 Gas;
 Telecoms;
PRIOR TO
WORKS
 Presence of live
underground services;
 Services not in area
specified on drawings;
 Heavy plant or
vehicles accessing
work area;
 Presence of
unmarked services;
 Risk of explosion due to gas line
rupture;
 Risk of flooding of trenches and
adjacent areas due to water main
damage;
 Risk of electrocution or fire due to
cable strike;
 Risk of hazardous waste entering
trenches or water systems due to live
sewerage damage;
 Risk of damage to low depth
underground services from heavy
vehicles;
 Risk of vehicles / Plant entering open
trenches;
4 3
12
HIGH
i. All existing utility service drawings reviewed for known service details and
position;
ii. NOC and Utility provider and ATC Excavation permits to be completed,
unique number added and recorded in log;
iii. Work Area, including access route for plant, to be CAT scanned to locate
exact position of service by competent persons;
iv. Service clearly marked on ground, using posts, tags etc.;
v. Plant access route to be indicated;
vi. Any unidentified services marked on ground and drawing by Temporary
Works Coordinator or Temporary Works Supervisor;
vii. All services clearly communicated to all workers at briefings and TBT’s,
signed off and recorded;
viii. Permit/NOC/JSEA/Approved design Drawings copies to be with task
supervisor in work area for review;
ix. Supervision and Plant Operators instructed to stay within designated area
and access route;
x. All trench barriers to be planned and to RTA Traffic Management Manual
if adjacent to live roads;
Workers not
complying with
controls
All supervision to monitor
operation;
Regular topic in TBT’s
LOW
2
Use of Excavator for
trial trenches and
backfilling
Note:
Wherever practicable
trial trenches shall be
hand dug to expose
services.
 Working with plant in
vicinity of workers;
 Working in vicinity of
underground services;
 Untrained operator;
 Workers struck by operating plant;
 Worker struck by reversing plant;
 Underground service strike;
 Material falling into trench;
 Damage to machine;
 Collapse of excavation due to
incorrect design/digging;
4 4
16
HIGH
i. Supervision and Plant operators instructed not to machine excavate within
1.5m of marked service;
ii. Hand digging only to expose services communicated, only use
shovels marked at 1.2m for guidance;
iii. All operators to be Third Party approved for the type of machine, licence
available for review at all times;
iv. Machine in – Men out mantra to be adhered to. No personnel shall be
inside the trench when the excavator is working, when personnel are
inside the trench the excavator shall rotate away and be isolated;
v. No personnel in excavation when pipes etc. are being lowered into
position, to stand outside of excavation;
vi. Banksman to control excavator movements; Spotter to assist operator to
observe and warn of any unidentified services;
vii. Daily checks on machine undertaken prior to commencing work;
Damage to
undetected
underground
services
Machine
breakdown
Hydraulic fluid spill
ATC Engineer shall
immediately contact
DEWA/Etisalat/Du as required
for action.
Area isolated.
Machine isolated and
quarantined until repaired.
Spoil removed and treated as
hazardous waste
LOW
RISK SCORE CALCULATOR
Use the Risk Score Calculator to Determine the Level of Risk of each Hazard
What would be the
CONSEQUENCE
of an occurrence be?
What is the LIKELIHOOD of an occurrence? Hierarchy of Controls
Frequent/Almost certain (5)
Continuous or will happen
frequently
Often (4)
6 to 12 times a year
Likely (3)
1 to 5 times a year
Possible (2)
Once every 5 years
Rarely (1)
Less than once every 5
years
Can the hazard be Eliminated or removed
from the work place?
Catastrophic (5)
Multiple Fatalities
High 25 High 20 High 15 Medium 10 Medium 5
Can the product or process be substituted for
a less hazardous alternative?
Serious (4)
Class 1 single fatality
High 20 High 16 High 12 Medium 8 Low 4
Can the hazard be engineered away with
guards or barriers?
Moderate (3)
Class2 (AWI or LTI) or Class 1
Permanently disabling effects
High 15 High 12 Medium 9 Medium 6 Low 3
Can Administration Controls be adopted
I.e. procedures, job rotation etc.
Minor (2)
Medical attention needed, no work
restrictions. MTI
Medium10 Medium 8 Medium 6 Low 4 Low 2 Can Personal Protective Equipment &
Clothing be worn to safe guard against
hazards?
Insignificant (1)
FAI
Medium10 Medium 4 Low 3 Low 2 Low 1
Project Name: xxx
RA Ref No.: xxx
RA compilation
Date:
Review date:
Date:
Compiled by:
Reviewed by:
Approved by:
Overall Task Details
Trial Trenches on site to locate/expose underground services. Use of excavator
Note: Wherever practicable trial trenches shall be hand dug to expose cables
Classed as Temporary Works
Relevant Applicable MAS:
 00246 – Excavations;
 01413 – Underground services;
 00940 – Plant Operators.
Additional Training required:
Temporary Works Coordinator to be designated
NOC’s Required for task:
Dubai Municipality

2. HEALTH SAFETY AND ENVIRONMENT Author: Approved:
RISK ASSESSMENT: 09 TRIAL TRENCHES (HAND DIGGING) TO MAS STANDARD
Issued: Rev. Date:
Revision: 0
Page 2 of 2 HSEQ -Rev-01(Jan-2023)
No
Specific Task Step
(In sequence of
works)
Hazard Details Consequence/Risk
Initial Risk
Rating Control Measures Residual Risks
Additional Control
Measures
RR
P S RR
3
Trench (shallow
excavation) open in
site area
 Trench in working
areas with live traffic
movements and
pedestrians;
 Unprotected
excavation area;
 Damage to exposed existing live
underground services;
 Trench collapse;
 Falling/slipping into trenches;
 Overturning of Truck / machinery into
trench;
 Incident due to poor illumination;
 Incident due to hazardous gas/fumes
entering trench;
 Collapse/damage of structures due to
undermining;
4 3
12
High
i. Temporary Works Coordinator / Construction Team to ensure Permit to
Excavate has been issued, communicated and signed by personnel prior
to any excavation/trench work;
ii. Excavation safety buffer, protection, design and traffic signs to be to ATC
Minimum Acceptable Standard, RTA Manual Chapter 3 requirements (as
applicable) and DM Code of Practice -Section 9;
iii. Any exposed services to be protected and adequately supported to avoid
damage;
iv. Any unidentified services discovered to be immediately communicated to
management and work stopped;
v. All spoil to be maintained at least 2m from excavation;
vi. Temporary Works Coordinator to ensure trench design adhered to at all
times;
vii. All trenches below 1.2m depth to be benched/battered back to MAS
standards;
viii. Trench to be inspected daily with written inspection report weekly by
Temporary Works Supervisor;
ix. Daily briefings to workers on working in excavations requirements by
supervision;
x. Use of stop blocks, barriers and other suitable means of protection used
to prevent vehicles entering trenches, warning tape is not to be used as
primary protection;
xi. Where practicable, access roads and pedestrian walkways to be
established away from trenches;
xii. Suitable and sufficient signage introduced to excavations;
xiii. Backfilling of trenches to be undertaken as soon as possible after
verification or completion of works;
xiv. Trenches to be suitably illuminated during night times;
xv. No changes without re-submittal of design reviewed by the TWC, NOC
and Permits;
Vehicle entering
trench
Trench collapse
Incident due to
barrier removal
Emergency services called,
area cleared
Secure area
No removal of protection
barriers without prior approval
from management.
LOW
5
Maintenance of
Trenches
 Adverse weather;
 Trenches open for
long periods;
 Damage to trenches due to incident
or adverse weather;
 Incident due to removal of barriers
3 3
9
Med
i. Trenches checked after heavy rains, severe winds etc., stand by pumps
to be available as required;
ii. Weekly recorded inspections undertaken;
iii. Implemented warning signage maintained;
iv. Housekeeping inside trenches to be maintained, all rubbish and waste
material to be removed daily;
Low
6
Worker exposure to
direct sun
(as applicable)
 Workers exposed to
high summer
temperatures;
Worker ill health due to:
 Heat exhaustion,
 Heat stroke;
 Heat Stress.
3 4
12
High
i. Summer Hour Working plan to be designed and implemented;
ii. Municipality summer working hours observed and implemented
(12.30pm to 3.00pm restricted in direct sunlight);
iii. Workers instructed regarding working in the heat and signs of heat
exhaustion etc. at Induction;
iv. Recovery cool rooms established on site;
v. Cool welfare areas established in all locations;
vi. Cool fresh water and electrolyte supplements to be maintained in all
areas;
vii. Pipe welders etc. provided with localised shelters;
New workers
bought onto site
Regular topic in Toolbox Talks Low