1.1 Flashcards
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
Actions to be taken in the event of an emergency in the work place may include:
- stop work
- assess the situation
- do NOT endanger yourself or other people
- inform first aiders
- follow emergency procedures
- contact emergency services
- contact the network operator/land owner
- inform supervisor
Emergency equipment required on site may include:
- sat phone
- first aid kit
- fire extinguisher
- spill kit
- rescue equipment
The action to take when rescuing a person from a LV line is:
- consider pulling the persons or conductors clear using approved insulated rods minimum of 3x 1.2m sections
The action to take when rescuing a person from a HV line is:
- no attempt should be made to rescue the person if they are in contact with a HV line
- the circuit may also re-close and there will be a voltage gradient in the ground
- only approach a casualty after the overhead line has been proven dead and earthed by the network operator
