Idea Transcript
TAKE 5 PAPER EXCAVATION AND TRENCHING
This information paper is to provide minimum guidelines about working in excavations and trenches to minimise risks to your safety.
EXCAVATION Excavation means a hole in the earth, or a face of the earth, formed after rock, sand, soil, or other materials are removed. Examples are trenches, ditches, wells, tunnels, cutting, or a hole drilled in the earth.
WHY IS AN EXCAVATION OR TRENCH A HAZARD? An excavation or trench can be a hazard if proper precautions and planning are not established prior to work commencing. Excavation and trenching ‘cave-in’ is a significant cause of death and serious bodily injury. Excavation collapse can result in: •
Death;
•
Suffocation - due to soil blocking the airways; and / or
•
Musculoskeletal injuries, i.e. injuries to bones and muscles.
WHS-T5-4.9.1
Created: 01/2007
Version: 4
Reviewed: 01/2017
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TAKE 5 PAPER EXCAVATION AND TRENCHING
SAFE WORK METHOD STATEMENT A Safe Work Method Statement must be prepared and documented prior to excavating or trenching a shaft or trench with an excavated depth greater than 1.5m; or a tunnel
RISK ASSESSMENT Before conducting any excavation and trenching work, a risk assessment should be conducted to identify potential hazards and risks. The risk assessment will be included in the Safe Work Method Statement. A template for excavation and trenching is available on Council’s intranet or from the WHSC.
UNDERGROUND SERVICES 1. Before excavation work is carried out for construction the following must occur: •
find out what underground services exist (Dial 1100 Before You Dig is a useful service);
•
obtain relevant information about the service (location, type, depth and restrictions to be followed);
•
give the information to the person doing the excavation;
•
record the information in writing;
•
follow any reasonable restrictions
WHAT ABOUT TRENCHES L5m DEEP? 1. The Supervisor is responsible for managing the risks associated with: •
an excavation collapsing;
•
a person being struck by and object falling into an excavation;
•
a person falling into an excavation, and
•
a person inhaling or being exposed to carbon monoxide from plant.
2. Following a risk assessment any control measures necessary to prevent risk from the collapse of another structure such as an adjoining building or road, must be implemented; and 3. A barricade at least 900mm high must be erected around a trench unless it is not practicable or only workers involved with the trench will be in the area, or another form of barrier exists.
WHS-T5-4.9.1
Created: 01/2007
Version: 4
Reviewed: 01/2017
Page 2
TAKE 5 PAPER EXCAVATION AND TRENCHING
WHAT ABOUT TRENCHES 1.5MT DEEP? The Supervisor must ensure that if a person is entering a trench more than 1.5 metres deep it:
1. •
has shoring or shielding;
•
is benched – not higher than it is wide and no vertical face exceeding 1.5 metres;
•
is battered – angle not exceeding 45° and bottom vertical face not exceeding 1.5 metres; or
•
is approved in writing by a geo-technical engineer as safe to work in.
2. Written approval to vary the benching and battering requirements may be obtained from a geotechnical engineer. The approval must be kept on site at all times; 3. Ladders used for access must be no more than 9m apart in the area of the trench where work will be carried out and must extend at least 1m above the ground; and 4. No petrol driven machinery in or near the trench.
SHORING, BATTERING & BENCHING All trenches should be shored, battered or benched: •
If the soil is unstable or prone to collapse;
•
If the trench is over 1.5 m deep and people have to enter it; or
Unless a Geo-Technical Engineer confirms in writing the walls are stable without shoring, battering or benching. Shoring, benching or battering of excavation walls are methods, which reduce the risk of soil or rock slipping into the excavation.
Benching
Battering
Shoring
WHS-T5-4.9.1
Created: 01/2007
Version: 4
Reviewed: 01/2017
Page 3
TAKE 5 PAPER EXCAVATION AND TRENCHING
SAFETY TIPS FOR AN EXCAVATION SITE To ensure workers safety in an excavation site, it is essential that the following actions be followed: 1. An excavation site more than 1.5 m in depth must be assessed to determine whether shoring or benching is to be installed to hold back loose soil. The outcome should be documented in the Safe Work Method Statement; 2. Ensure that heavy earth moving equipment is kept back from the edges (eg. at least 1m) of any excavation or trench; 3. Equipment, soil or other material must be placed as far as practicable from the edge of an excavation or trench; 4. At least one other person should remain at ground level at all times, so that in the event of a collapse, the person at ground level will know where the trapped person is located; 5. Enter or exit into or out of an excavation should be by a ladder only. The ladder or set of steps must be located within 9m of either end of the excavation or trench at all times; 6. No petrol driven vehicles are allowed in the excavation, due to the fumes created; 7. Ensure the excavation is barricaded if hazards are present or if it is accessible to those other than workers working at the site; 8. If the excavation is to be left open for an extended period of time, the excavation is to be checked daily for cracks, slides and scaling and inspection results must be documented; 9. During rain and other hazardous weather conditions, checks should be done more often; and 10. Check overhead power lines before excavation begins.
‘Remember - following a few simple rules can save your life!’
WHS-T5-4.9.1
Created: 01/2007
Version: 4
Reviewed: 01/2017
Page 4
TAKE 5 PAPER EXCAVATION AND TRENCHING
Take 5 Quiz EXCAVATION & TRENCH SAFETY
CIRCLE THE ANSWER YOU BELIEVE IS CORRECT. 1.
The most significant form of death in an excavation or trench is cave-in? True
2.
I would not need a work method statement for any trenching work over 1.5 m deep? True
3.
False
If a trench was over 1.5 m deep, a ladder located within 9 m of each end of the trench would be required for entry and exit? True
8.
False
I would conduct a risk assessment before conducting any trenching work? True
7.
False
Any trench over 1.5 m must be either shored, benched, battered or have approval from a GeoTechnical Engineer not to do any of the above? True
6.
False
Because the trench I was working on was only 1m deep, I would not need to barricade it? True
5.
False
If I was digging a hole or a trench, I would ask my Supervisor to call 1100 Dial Before You Dig? True
4.
False
False
I would always ask for and check the Safe Work Method Statement before I did any trenching work over 1.5 m deep? True
False
9. If there was no safe work method statement available for trenching work over 1.5 m, I would still do the job? True
False
ACKNOWLEDGEMENT RECEIPT I have read and understand the information provided to me for Excavation & Trenching and I have been issued with the Take 5 Paper. ______________________ Employee’s Name ______________________ Supervisor/Trainer’s Name
WHS-T5-4.9.1
Created: 01/2007
______________________ Employee’s Signature ______________________ Supervisor/Trainer’s Signature
Version: 4
Reviewed: 01/2017
__/__/__ Date __/__/__ Date
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