There are two methods for pressure tests: hydrostatic and pneumatic.
A hydrostatic test is performed by using water as the test medium, whereas a pneumatic test uses air, nitrogen, or any non-flammable and non- toxic gas.
The fluids most commonly used for a pneumatic test are air or nitrogen. However, pneumatic testing involves the hazard of the piping system retaining stored energy that could have a very damaging effect if there is a failure.
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| Hazard Category | Hazards | Controls |
| Failure of Pressurized System | 1. Can occur if the pressure exerted on the system exceeds its design capabilities or if any part of the system fails during pressurization i.e. a weld | 1. Supervisors and/or responsible persons shall ensure that all measurements and calculations have been carried out prior to testing to establish the amount of pressure, Which is to be exerted on the system
2. Checks shall be carried out prior to pressure on all welds, etc. to identify any possible weak areas.
3. Checks shall also be made to ensure that all connections, joints and plugs in the system are secure.
4. No tests shall be carried out without a company;s test procedures.
5. Only certified materials, plant and equipment shall be used. A copy of all certificates shall be obtained along with the test pack. |
| Failure of Pressurized Hoses | 1. Can occur if hoses, etc. have not been constructed and maintained in a safe working order | 1. All personnel shall ensure that all equipment to be used in the testing process is safe and without defects. Only certified material and equipment shall be used.
2. All personnel shall ensure that approved “R Clips and Whip lines” are fitted between hose connections, to prevent hose seperation. |
| Inadequate Emergency Procedure | 1. Injury potentials can be greatly increased if suitable emergency procedures have not been established prior to work commencement. | 1. Managers/supervisors and/or responsible persons shall ensure that suitable emergency procedures have been implemented prior to pressure testing. such procedures and arrangements shall be discussed with the workforce. Tool box talks shall be held prior to work stating.
2. In order to establish suitable emergency procedures, managers/supervisors and/or responsible persons shall carry out an assessment of the following. The area of work, the number of personnel involved, suitable access/egress to the work area, location of first aid and fire fighting facilities, accessibility to emergency services, etc. |
| Carrying out Repairs on Pressurized Systems | 1. Serious injuries can occur if personnel proceed to undertake maintenance work on the system while it is under pressure. | 1. No worker shall take place on pressurized system.
2. Supervisors and/or responsible persons shall ensure that the system has been depressurized prior to any maintenance work.
3. All personnel involved in the pressure testing operation shall be competent and a designated “Responsible Person” present at all times.
4. All procedures associated with pressure testing and relevant safety precautions shall be obeyed.
5. Systems under pneumatic testing will not be subject to any shock loading (i.e. hammering etc.) |
| Conflicting Acticities | 1. Accidents can occur if other activities are carried out near the pressurized system which could have an impact on the safety system, i.e. crane lifting operations overhead. | 1. Supervisors and/or responsible persons shall ensure that no activities (which could have a direct impact on testing operation) are carried out during the testing process.
2. All area involved in the test shall be barriered off and signs erected to warn other personnel. |
| Inadequate System of Work | 1. Serious accidents can occur if a “Safe system of Work” has been implemented prior to work commencement. | 1. A “Safe system fo Work” shall be implemented for all pneumatic tests.
2. Tool box talks shall be held & documented with the work force.
3. All necessary barriers and notices shall be displayed.
4. Only authorized persons shall be permitted inside the barriers. |
사우디아라비아에서 근무했을 때, Tank 상부 뚜껑(덮개)를 공압을 이용하여 설치하는 공법이었습니다.
Tank 벽체 내부에 Tank 덮개(cover)를 용접 시공한 후에,
공기압으로 Tank cover 위치까지 인양하여 상부에서 고정하여 시공하는 방법으로,
제 기억이 맞다면 지름 약30m 정도 Cover를 들어올리는 압력은 1 bar 이었습니다.
Pneumatic Test를 할 때에 많게는 백단위 Bar까지도 압력을 걸어야 함으로써, Test 중에 파손위험으로 안전거리 확보가 무엇보다 중요합니다.
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Pressure Testing Safe Distance
첨부된 파일 확인해보시구요. 26. Nitrogen Testing 같이 확인해보세요~
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