Risk assessment process may contain the following 5 steps:
- Identify the hazards
- decide who may be hurt and why
- evaluate the risks and decide on precautions
- record the findings and implement them
- review and update the assessment as necessary
Generic risk assessment:
- use of chainsaw and machinery
- procedures of working at height
- procedures of live line and deadline working
- repeated tasks and procedures
- other
Site specific risk assessment:
- Detailed hazards specific to site, tasks carried out, and work.
- safety of public, property, and environment
- details of trainees and supervisory levels.
- other
Electric risk assessment:
- Electric and tree related hazards clearly separated
- Justification of any live working proposed
- category of tree works clearly defined I.E Cat A-D
- other
Requirements of appropriate site supervision may include:
- name of operative(s) being supervised with age if relevant
- operations being supervised
- the supervisor(s)
- level of supervision
- details documented i.e within risk assessment
- arrangements agreed with network operator
- other
Emergency planning relevant to a work site may include:
- site location
- grid references with prefix
- what three words
- designated meeting place
- nearest access point
- street name/district
- type of access
- suitable for helicopter landing
- nearest emergency services
- phone number for closest doctors
- works manager contact details
- your own contact details
- other
PPE that is required where appropriate:
- high vis clothing
- head protection
- hand protection
- foot protection
- Eye protection
- hearing protection
- specialist equipment as specified by network operator
- all ppe should comply with latest standards
Proximity zone one:
- All trees that are to be felled within two tree lengths of any live equipment
Proximity zone two:
- all trees to be dismantled, pruned or have other arboricultural work carried out on them that are within the following:
9m of any live equipment up to 66kv
15m of any live equipment over 66kv
- only certified and competent operatives may work within proximity zones without any appropriate supervision of the network operator
Factors to consider with proximity zones when felling:
- Network operator must be advised if work is to take place in proximity zones
- distance is measures horizontally from a point directly beneath the nearest conductor to the base of the tree
Factors to consider in proximity zone when machinery is being used:
- stated distances will be measured to the nearest point to the line that any part of the machine or load can reach
Factors to consider proximity zone on slopey ground:
Increase the distance to allow for the effect of the slope so that the task can be carried out safely
- the distance must be reassessed on the re commencement of work
Definition of the vicinity zone:
- the zone around an exposed live circuit conductor which if maintained will prevent the danger of burn or electric shock
- the live zone is included within the measurement of the vicinity zone
The vicinity zone distances for the following range of voltage:
- LV = 1m
- 11kv = 2m
- 33kv = 2.5m
- 66kv = 3m
- 132kv = 3.5m
- 275kv = 4m
- 400kv = 5m
Factors to consider when applying the vicinity zone distance to a task:
- different measurements for different voltages
- the higher the voltage, the greater the distance so always select the greatest distance if in any doubt
- if the vicinity zone distance is maintained it will prevent injury
Definition of live zone:
The zone around the exposed live circuit conductor where the danger of a burn or electric shock can occur if any part of a body or non insulated tool that is being used enters the zone.
The live zone distances for the range of voltage:
**Lv = 0.3m
**11kv = 0.8m
**33kv = 0.8m
**66kv = 1m
**132kv = 1.4m
**275kv = 2.4m
**400kv = 3.1m
How to prevent injury to site personnel:
- ensure the work is carried out as defined by the risk assessment/method statement
- maintain safety distances
- always maintain awareness of vicinity zones, particularly when moving and handling timber and branches
- locate underground cables and protect where necessary
- locate other utilities I.E gas, water or sewer.
Factors to consider when working in the designated area and when leaving the site safe for others:
- ensure work does not interfere with other parties
- always maintaining the general safe condition of site during and after work
- ensure logs/brash/chippings are stacked clear of the line
- acces points / Egress points kept clear
- remove site spoil where appropriate
- fences, ditches, paths, young trees, badger setts etc. Must be left undamaged
- tools and equipment all removed from site
- any hanging branches removed
Factors to consider when carrying out ground work operations:
- do not face the chipper in the direction of conductors of equipment
- do not leave long branches on site where they can be handled later and breach vicinity zones
- ensure a clear path is left under the conductors to allow access for future patrols and maintenance
- do not stack timber adjacent to substation boundary fences that may allow climbing access
- ensure that hanging branches are not left as a hazard for others
Tree type and condition may change the electrical danger:
- species different sap levels e.g willow will have high sap levels
- spring = rising sap levels
- full leaf/dead tree
- trees with leaves may come into contact with the overhead line
Factors to consider when using ladders adjacent to overhead lines may include:
- do not use metal ladders
- wet/dirt on wooden ladders increase conductivity
- fiber glass ladders may offer better protection but they’re not rated as insulated
- always carry in a horizontal position as close to the ground as possible
- never allow ladders to enter the vicinity zone
- ladders must be of a type/ construction approved by the network operator and only used in accordance with permitted procedures
Safety considerations when using ropes adjacent to overhead lines:
- rope material as no ropes are rated as insulated
- wet ropes increase conductivity
- dirty ropes increase conductivity
Ways to reduce the danger when working with ropes near to overhead lines:
- ropes should only be placed in trees using insulated rods
- never use lines/ throw bags
- never throw ropes from the ground
- all ropes in use must be secured so they don’t enter the vicinity zone
- all ropes used climbing must be used the side of the tree furthest from the line
