/ Health & Safety OPERATIONS STANDARDS Ref.: Aperam Safety ST 012 Working in Gas Hazard Areas Issue: 15.05.2012 Vers.: v0 Rev.: AM Safety ST 012 v1.2 08.05.2012 Working in Gas Hazard Areas Controlled Updated by: Validated by: Approved by: Circulation Name : Edméa Azevedo Leonam Almeida Ilder Camargo 1. Scope 1.1. This standard describes minimum requirements for working in a potentially hazardous gaseous environment (Gas Hazard Areas), to prevent the formation of explosive mixtures or zones of explosive atmospheres, a build up of asphyxiate or toxic gas (incl. gases taking the place of O 2 ), or to manage the oxygen levels to prevent either extremely rapid combustion or suffocation (harmful atmospheres). It covers permanent Gas Hazard Areas are areas such as blast furnaces and coke plants, areas with combustion gases or gases coming from DRI plant, by-products treatments, combustible and / or solvents tanks, gasoline powered engines in partially enclosed areas but does not include confined space entry requirements which are covered separately in Aperam Confined Space Standard (Aperam Safety ST 002) with specific procedures. So both standards must be considered together. 1.2. It is mandatory to comply with local regulations. In addition, this standard must be applied when it is more demanding than local regulations. 1.3. This standard does not apply to the underground part of the mine site. For that part of the mine specific regulations apply, according to the standards and law in the relevant countries. However this standard does apply for the gas hazardous areas at the surface part of the mine. 2. Gas Hazard Areas 2.1. Each site must have a documented and up to date risk assessment for each area and task associated with working in potentially hazardous gaseous environments. 2.2. Each site must have an up to date layout plan in which all Gas Hazard Areas are highlighted and in the operative pulpit a system of alarms particularly for levels CO. 2.3. Safe work and purge procedures shall refer to the risk assessment and specify appropriate controls for all work. These should include at least items such as the required hot work, PPE, purging and permitting, monitoring, isolation, consideration for using a safety stand-by person; the emergency response should be included in the risk reduction strategy. This is to be completed with any relevant specific local condition. Health & Safety 1
2.4. All such areas highlighted by the risk assessment shall have appropriate warning signs posted and a permit system for controlled access to authorized employees and contractors must exist. 2.5. Working in the area of chimneys, where combustion gases are leaving, is considered as a gas hazard area. 3. Competencies 3.1. Each person (including contractors) working in Gas Hazard Areas must be appropriately trained in the specific tasks as well as the emergency procedures. 3.2. Training contents and list of people trained must be documented. Trained people must be able to identify themselves (certificate). This certificate is limited in time and renewable periodically. 4. Procedures and Permitting 4.1. A risk assessment must be used to develop the most appropriate safe work procedure and shall include an assessment of areas (inside as well as outside the plant) that may be affected by any release of gas. 4.2. There must be a process where a written permit (one time task) or a written procedure (repetitive or continuous jobs) is used to plan and control the work involved in isolating, purging and making the area safe for maintenance and other activities. All isolations made to render the work safe must be physical isolations and follow the Aperam Isolation Standard (Aperam Safety ST 001). 4.3. Appropriate gas monitoring must be done before, during and after work has been completed. In some cases, defined by a risk assessment, monitoring may not only include displaying, but also include e.g. audible, vibration and warning lights alarms. Use of more than 1 monitor at the same time to measure before entering provides extra security and is thus to be practiced. Monitoring before the job may require use of individual respiratory equipment; this has to be included in the task description based on the risk analysis. This monitoring must be done by trained and certified people. 4.4. There must be a method to ensure supply of air (see also 5). 4.5 Prohibition of smoking or open flames in gas hazard areas. 4.6. Hot work (welding, soldering, braising, cutting, ) carries the risk of fire; as such, in a gas hazard area, these tasks may only be carried out after a duly authorized permit for hot work' has been issued. 5. Air supply 5.1. Any supply of air is to be according the quality specified in prevailing local regulations. Health & Safety 2
5.2. As a minimum Compressed breathing air shall meet at least the following requirements: - Oxygen content of 19.5-22.0 %; - Hydrocarbon (condensed) content of less than 5 milligrams per cubic meter of air; - Carbon monoxide (CO) content of less than 10 ppm; - Carbon dioxide content of less than 1000 ppm; and - Lack of noticeable odor. 5.3. Breathing apparatus must not be supported by the use of portable compressors for air intake. 5.4. There must be a method, incl. documentation and testing information per apparatus, for assuring the functionality and condition of all components of breathing apparatus such as mask seals, mask visibility, valves for control of breathing, cylinder regulation, pressure measurement and hoses. 6. Comments 6.1 A systematic plan for revision of leakages in gas hazardous areas must be drawn up and put in practice. 6.2. All pipes will be painted using normalized colours, especially in maintenance zones. 6.3. Gases regulations will strictly be applied during design of any construction, taking into account open spaces or enough ventilation. 6.4. Avoid O 2 close to any combustible in restricted zones, particularly for grease, oil, and other lubricant products. 6.5. Gasoline-powered tools should best be used outdoors to avoid combustion gases inside the workplace. If in a building, proper evacuation of the combustion gases to the outside of the building is needed, as well as ventilation. Continuous measurement of the presence of dangerous gases, with alarm at the entry of the building, is considered best practice 6.6. Never use O 2 instead of compressed air for cleaning purposes. 7. Detectors 7.1. Generally, use multi-gas detectors. 7.1.1. Exception : when the highlighted Gas Hazard Areas layout plan, based on a risk analysis, permits adapted specified detectors 7.2 When the risk assessment requires some portable gas detectors must be used to enter into a gas hazard area, each worker (own people as well as contractors) must be individually equipped with an appropriate individual detector. Each user must be trained to the proper use of the considered detector and will assume the responsibility and discipline to maintain it in a good state of use. The use of a single portable detector for several workers is not recommended even when they work together because depending of the gas density, it s concentration in the atmosphere can change from the location where the detector is to another one only 1meter away. Health & Safety 3
7.3. There must be a system in place to inspect all equipment and to test and calibrate all gas monitoring devices (fixed and personal) 7.4. CO-detectors Thresholds to be used must not be higher than : 30ppm for low level, enabling 8h time of presence 100ppm for high level, enabling 1h time of presence See CO hazard curve in attachment. 7.5. O2 Two levels of detection to be used; recommended values are : Low 19,5 % High 22,5 % Do not forget : the detector reaction time is NOT immediate; it takes 10 to 20 sec to establish the proper measurement. This must be taken into account in the local procedures. To be clear : the detectors used must be able to detect both limits since having lower or higher values may both lead to fatalities. 7.6. Explosion Risk Explosion risk is detected through hydrocarbons (mainly CH4) and expressed in % of Low Explosion Limit (LEL); The 2 levels are recommended not to be set higher than 10% resp. 20% of LEL. 7.7. H2S This measurement is required if H2S is contained in gases (for ex COG) but also created by decomposition of organic matters (for ex in water pits) Recommended detection levels : Low 5 ppm High 10 ppm 7.8. Calibration There must be a system in place to inspect all equipment and to test and calibrate all gas monitoring devices (fixed and personal). Calibration has to be done strictly according to the prescriptions of the supplier (frequency and method). Health & Safety 4
Calibration has to be documented per detector. So all detectors have to be numbered Calibration is to be done by certified personnel (supplier or properly trained own people). 7.9. Procedures Local procedures must describe actions to be taken for each alarm level for each type of gas alarmed by the detectors. 8. Emergency Response 8.1. Unexpected release of gas must be included in the site s overall emergency response plan and must consider all potentially affected areas on and off the site. The emergency response plan must include the type, inspection and location of appropriate emergency rescue equipment. 8.2. Emergency response plans must be regularly practiced and evaluated according to the risk assessment. Health & Safety 5
Attachment POISONING WITH CARBON MONOXIDE (CO) Health & Safety 6