Procedures for entering confined space
Confined space entry procedures are critical; before any worker enters a permit-required confined space, a system of procedures and precautions must be followed.
It is essential that supervisors, standby workers and entrants all know the confined space specifics. Correct equipment must also be on hand to help ensure worker safety.
The following procedures must be followed:
- Completion of a Risk Assessment
- Signage and Barricading
- Isolation of Hazards
- Cleaning, Purging & Ventilation
- Atmosphere Testing & Monitoring
- Completion of an Entry Permit
- The Role of the Standby Person
- Rescue & Emergency Plan
Completion of a risk assessment
First step before even considering undertaking work within a confined space is to complete a thorough risk assessment. Risk assessments come in various forms including JHA (Job Hazard Analysis) or SWMS (Safe Work Method Statement). The purpose of a risk assessment is to:
- Identify all hazards.
- Identify the tasks that are required to perform the job.
- Review methods used to complete the tasks.
- Identify the hazards involved and the associated risks related to the method required to complete the task.
- Creation of emergency response procedures.
- Assess the competence of workers to perform the task.
Signage and barricading
In conducting work in and around a confined space, a person in charge also has the duty of care to those in the vicinity of the confined space. A confined space sign is required to prevent persons not involved in the work from entering. To further reduce this administrational risk control, it is also highly recommended that the area be barricaded off to isolate the area and allow access only to authorised entrants and standby persons.
Isolation of hazards
Some of the hazards that may be identified during the risk assessment include the presence or introduction of contaminants through connections to the confined space such as piping, ducts, vents, drains, conveyors, service pipes and fire protection equipment, mechanical or electrical machinery that contains moving or energised parts and plant services such as heating or cooling equipment. Isolation is another form of risk control which involves locking, tagging, closing and blanking the isolation point to ensure it is not accessible during confined space work.
This may include locking out an inlet valve or releasing stored energy in hydraulic, pneumatic, electrical, chemical, mechanical, thermal or other types of energy. Good practice recommends that the hazard be isolated and locked by entrance and standby persons, and are not removed until all people have left the confined space.
Cleaning, purging and ventilation
Cleaning, purging and ventilation are all methods used to ensure that the confined space atmosphere is clear of any contaminants that could harm any persons entering. Purging is a method that is used to displace the contaminants from the confined space where ventilation is a process of continually moving fresh air through an area via national, forced or mechanical means. Cleaning when feasible should be conducted outside of the confined space, but may require entry to complete the task. The purpose of these three methods is to dilute or displace harmful gases, maintain a safe oxygen level and prevent the build-up of dangerous gases or materials.
Atmosphere testing and monitoring
There are specific hazards associated with harmful vapours and gases.
It is important to ensure that the concentration of any flammable gases, vapours or mists in the atmosphere of the space be less than 5% of its LEL.
If this is not practicable, workers must ensure that a calibrated continuous monitoring flammable gas detector be used while the atmosphere concentration is equal to or greater than 5% but less than 10%. If the concentration is equal to or exceeds 10%, all persons must be immediately removed from the space. Prior to entry the atmosphere must be tested and recorded. Initially this should be checked external to the confined space, around entry points and immediately inside.
Completion of an entry permit
A confined space entry permit must be completed before work can be conducted inside the space. It is a formal check to ensure that a safe work system is in place as well as a means of communication between site management, supervisors and those who carry out the work.
The permit must be completed by a competent person and specify the confined space to which it relates, names of persons permitted to enter the space, the time period which the work in the space will be carried out and measures used to control the risk associated with the proposed work in the space. A space must also be left for acknowledgement and sign off that the confined space work has been completed and all persons have left the confined space.
Rescue and emergency plan
The last critical piece of documentation required prior to entering a confined space is a rescue and emergency plan. It must be developed as per the regulations and rehearsed and practised by confined space teams prior to entry.
Consideration of the emergency plan should also be taken into account when designing or reviewing the space.
The entry space must be large enough to allow emergency access and the appropriate first aid, PPE and other rescue equipment is available, maintained and in good working order should it be required.
This should also be a dynamic document as the environment and circumstances may change quickly.
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