EMESRT RISK: Risk of injury due to stored energy systems, such as accumulators, with no means to isolate or reduce to zero energy. Click to view this EMESRT Risk Failure under pressure All mines are strongly advised to conduct an audit / inspection of all pipe ranges to determine if any areas of potential failure exist and to replace suspect pipes. LTA competency procedure This high voltage is a danger to all tradesmen working on this type of light fitting and certain precautions should be taken to ensure personal safety as follows: 1. Any competent tradesman can change a complete light fitting. 2. Only electricians who are competent in the working on this type of light fitting may disassemble and repair them. 3. The light fitting should be totally disconnected from power (24 Volts) before being disassembled. 4. The light should also be disconnected from power for a minimum of 5 minutes before being worked on. This will allow any stored energy to be safely discharged before internal terminals are exposed. 5. When faultfinding and repairs are complete, the light fitting is to be fully and completely assembled before testing on 24 Volts. 6. All lights should have an appropriate warning sticker put on the top of the fitting before they are installed. Page 1
LTA Standard Work Procedures (SWP) Compressed air is an energy source that has the potential to cause extensive damage and injury if it is not controlled. Mines must ensure that controls are implemented to ensure the risk to those working on compressed air lines is at an acceptable level. People must be competent and familiar with the correct procedures and standards before working on compressed air systems or lines. As with any work involving stored energy, strict isolation procedures must to be adhered to before commencing any work on compressed air systems. All mines and quarries should ensure isolation procedures are in-place to cover the isolating, de-pressurising, testing, and the returning to service of compressed air systems. Guidance notes for development of isolation procedures can be accessed on the Mines Inspectorate web page at: www.nrm.qld.gov.au/mines/publications/pdf/isolation.pdf Along with the recent fatality there have been several other documented incidents over the years where not only compressed air but also other pressurised substances have caused extensive damage and personal injury. In particular, refer to Safety Alert No1 "Failure to Isolate Compressed Air Line issued on 20/1/2000 by the Queensland Inspectorate which states: In an Underground coal mine two parallel pipe branches comprising a 100 mm compressed air line and a 100 mm pump line had been installed. The task was to install pipe closures to join these pipe branches to the main line. Tee pieces had been installed into the main lines to receive each of the branches. All the pipes were suspended from the roof by chains. Connected to each Tee section in sequence were a 100 mm butterfly valve, 25 mm valve and an end cap. Both these lines were 100 mm galvanised pipes with Victaulic clamps of the quick release lever type. The pump line closure had been installed and preparations were being made to install the airline closure. The 100 mm butterfly valve on the airline had been closed and the end of the tee section bled of pressure through the 25mm valve. A miner was attempting to remove the end cap by releasing the quick release clamp. The end cap was ejected from the end of the pipe under pressure striking the miner in the face causing severe injuries. All workers should be made aware of or reminded of the hazards associated with compressed air systems and lines. Management at all mines and quarries need to have developed and then periodically review isolation procedures. These procedures should address the ability to safely isolate all forms of energy and pressurised systems including compressed air. Page 2
Failure under pressure LTA risk assessment The following practices are recommended: Isolation, bleeding and checking of service lines prior to any work being carried out on them. A sufficient number of cut-out valves and bleed valves must be placed in lines at convenient points as they are installed or extended, to enable this precaution to be carried out readily. Special precautions should be taken to ensure effective isolation and adequate bleeding where branches in the pipe range or the use of "ring-mains" may allow a line to remain pressurised from more than one source. Careful checking of the integrity of joints in pipe ranges, prior to re-pressurising of the line, in order to ensure that couplings are not damaged and seals are adequate. Regular routine checks of pipe ranges to ensure that suspension of the line is adequate to support its weight and any additional loading which may be imposed by pressure variations in the system (e.g.. "water-hammer" in pump lines). Where necessary, additional suspension points should be installed. Checks should be made particularly after the suspension of one line from another using "C" hooks or similar devices, or where additional services such as cables or ventilation duct may be suspended from the original pipe-hangers. Restraint of pipe ranges whenever it becomes necessary to break a line, so as to prevent the sudden and unpredictable release of tension in the line itself with consequent "springing" of the line and the possibility of workers in the area being struck by a suddenly moving pipe. This is particularly important where work is being carried out in the vicinity of a change in the direction of the pipe range. Proper installation of pipe ranges with an adequate number of correctly angled bends to accommodate changes in the direction of the pipe run. Use of pipe and fittings adequately designed for the duty they are required to perform. Page 3
Damaged or badly worn pipe or fittings should not be used. It should be remembered that the same precautions are necessary where "poly" pipe ranges are used as for metal pipe and fittings. The long lengths of "poly" pipe which are frequently installed present an additional hazard in that, should one end of a pressurised line become detached, the line (being flexible) can escape its restraints or suspension devices and snake or whip under the action of the pressurised fluid or gas which it contains in much the same way as a hose which has burst off its fittings. Given the large amounts of energy involved, the potential for injury is extreme, both from flailing pipe and from "sand-blasting" by the released fluid or gas. LTA safety warnings LTA use of restraining device Employers should ensure that their employees are fully aware of the potential hazards and risks associated with any task to which they are allocated. Maintenance employees who are about to undertake a task which they have not attempted before or who are unsure of the correct way to carry out a job should consult the manufacturer s instruction manual and discuss the matter with the supervisor to clearly establish a safe working procedure. A means of controlled discharge should be available whenever stored energy sources may be released during maintenance work. LTA risk assessment Page 4
LTA use of restraining device Supervision should ensure all reasonable precautions have been taken to provide a safe workplace. A job safety analysis should have highlighted the fact that the belt was not secure and developed a safe working procedure to eliminate this. Management should clearly define the role and responsibility of each supervisor so that each workplace is under the control and supervision of one person. Failure under pressure LTA Standard Work Procedures (SWP) LTA maintenance procedure LTA pressure control LTA procedures LTA safety warnings LTA supervision The absence of flow, or a mere trickle, emanating from a drain valve on a pressurised vessel may lead inexperienced or incautious personnel to assume that the vessel is empty or at least no longer under pressure. In fact this no flow condition is usually brought about by the presence of a blockage of some sort. Upon opening the vessel to investigate the cause of the blockage, the pressurised contents are then released, spraying those personnel in close proximity. Clearly the main preventative action in this case is the existence of a safe system of work for opening the pressurised vessel. This should incorporate a Closed Vessel Procedure which adequately covers the safe isolation and depressurisation of the vessel prior to opening. The actual opening of the vessel should be carried out according to a written procedure which includes references to the required PPE needed to safely perform the task, and should be carried out only by personnel who have been previously trained and undergone competency testing. Page 5
LTA positioning of body LTA use of restraining device In accordance with Section 9 of the Mines Safety and Inspection Act 1994, employers are required to ensure that a safe system of work is developed for any work being undertaken. Where procedures are not available, employers should utilise job safety analysis (JSA) mechanisms to document the task, identify the risks and specify the safety controls to be used prior to the work being undertaken. All maintenance work needs to be regularly monitored and supervised throughout the shift to verify compliance with safety requirements, identify any deviations from safety standards and ensure alternative safe work methods are put in place to correct these deviations. Additional assistance should be made readily available on demand to employees working alone, to ensure that they do not over-extend themselves. Identified hazards should be managed and controlled in accordance with the hierarchy of control. The aim of a good risk analysis should be to eliminate the hazard, substitute a safer method or engineer out the hazard, in preference to accepting the risk and writing more safety rules, providing personal protective equipment (PPE) or both. Where the removal of moving machinery is impracticable, guarding of all pinch points and moving machinery parts is essential in protecting employees from inadvertent access. In accordance with Australian Standard AS 1418 Cranes, hoists and winches, all fixed EWP equipment and any external auxiliary pump, when used to operate an EWP, must be fitted with check valves on the lift ram circuit to prevent a rapid descent of the EWP due to any failure of the hydraulic circuit components. Page 6
Where manually operated devices are installed for the purpose of external control of a EWP (as in the case of the manual ball-valve in this instance), they should be located outside the range of influence of the moving parts of the unit. All portable equipment should be regularly checked and maintained in an operational condition. Toggle switches that become defective should be replaced. LTA pressure control Specific recommendations are not available until the investigation nears completion. All mines should include the management of high-pressure fluid systems as an integral part of their mine safety management system which should include: 1. A comprehensive Management Plan to manage the risks associated with high-pressure fluids. 2. A review of previous injuries, accidents and significant incidents due to high pressure hydraulics. 3. A hazard awareness program to include the dangers of high-pressure hydraulics and oil injection. 4. Appropriate levels of competence for persons accessing high-pressure hydraulics. 5. A clear isolation policy on what work can and cannot be conducted on equipment that is pressurised. A process to positively isolate the system or parts of a system by lockable means. 6. A process to identify if pressure is contained in a system and a means to drain pressure from a system without disconnecting fittings. 7. A process to take fluid samples from a system safely without the need to disconnect fittings and access to high-pressure points for sampling using specific purpose-designed equipment. Fit for-purpose equipment suitable for the intended use must be used. Page 7
8. Clear identification of high-pressure, medium-pressure and low-pressure fluid lines. LTA Isolation hardware LTA design LTA risk assessment 1. Mines consult with the OEMs for the recommended procedure and equipment to install and remove the roof supports. 2. Review the equipment and components of the installation and recovery hoses for fit for purpose application. 3. The isolation valves should be the positive lockable type and the bleed valve (lockable type) should be capable of releasing the hydraulic pressure in a controlled state. 4. All procedures should include positive isolation instructions i.e. use lockable hydraulic isolation valves, with bleed valves that release the hydraulic pressure in a controlled manner away from all employees,(use a diffuser refer photo 3) and the depressurisation must be proven e.g. with a pressure gauge (Refer Drawing 1). 5. The pressure line must be connected to the relative ports, and return line must be connected back to tank at all times. 6. The hydraulic system must have pressure relief in the event of over pressurisation. 7. If possible reduce the installation pump pressure (e.g. from 350 Bar to say 150 Bar) to activate the roof supports. (Usually reduced pressure is used on the installation face not the recovery face) 8. Review SA05-01 Change Work Practices, Employer Obligations. 9. Review the OH&S Regulations 2001 Chapter 5 10. The pressure and return lines for PTO should be different sizes (e.g. DN10 & DN13). 11. Best practice is to interlock the isolation valve and the bleed valve so both valves cannot be open at the same time (Refer to Drawing 1). Alternatively a system could be developed with the equivalent level of safety. Page 8
LTA PPE LTA equipment LTA pressure control LTA procedures 1. Design equipment with safe systems to either (a) allow grease to flow through the system or reside in a pressure system (piston), and (b) allow for controlled pressure release. 2. Assess equipment and identify areas where lubricants or other fluids could be trapped under pressure in systems and implement measures for maintenance personnel to control the activity. 3. Ensure fit for purpose equipment, i.e. the correct matching thread for a fitting, is used. 4. Review competence of persons engaged in pressure lubrication activities and conduct hazard awareness training with personnel to enable identification of stored energy. 5. Ensure that persons are provided and wear appropriate eye protection for the tasks being performed. LTA positioning of body LTA use of restraining device Best Practices Conduct a Risk Assessment before beginning any task; evaluate the work procedures, identify all possible hazards, and take steps to perform the task safely. Page 9
Establish safe work procedures and ensure all personnel involved communicate clearly with each other. Never work in a location where co-workers cannot see you during loading or unloading of materials. Ensure that workers are not positioned near hazards from falling loads. LTA safety device operation Best Practices Conduct a Risk Assessment before beginning any task; evaluate the work procedures, identify all possible hazards, and take steps to perform the task safely. SLAM it. Stop, Look, Analyse, and Manage. Position ladders for protection from moving objects, or being bumped or knocked over. Never work beneath a suspended load. Securely block equipment from motion when working around it. Use fall protection and tie off where danger from falling exists. Examine all tools, including ladders for defects and remove any defective tool from the work area. Assure that moving parts operate freely without binding or excessive play. Page 10