2. REVISIÓN BIBLIOGRÁFICA
2.5. Toxoplasmosis animal
2.5.2. Toxoplasmosis ovina
Hydrogen sulphide surveys are required to ensure that persons are not exposed to continuing or intermittent injurious levels of hydrogen sulphide Initial scoping studies for finding potential areas of hydrogen sulphide exposure can conveniently be carried out using hand held electronic monitors, these are available with sensitivities in the ppb region, but for TWA measurement purposes, instruments which measure down to the 0.1 ppm level are more suitable, and more readily available as standard industrial equipment. Instruments with a probe are often more convenient for identifying the source of small releases from valves or rotating equipment.
Once the hydrogen sulphide survey has been defined, the survey can be carried out using dosimetry badges, absorption tubes, or personal recording monitors.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 4 CONTROL
4.1 PERMIT TO WORK
All facilities where a hydrogen sulphide hazard exists must operate a Permit-To-Work system. Permits-Permit-To-Work in Yellow and Red zones must not be issued without pre-work site inspection, which must include as a minimum:
determination of potential for release, a task risk assessment (TRA), correct isolation, appropriate controls/PPE, buddy system and requirements for continuing detection.
All lockouts, interlock removal, including the movement of locked valves and similar operations undertaken in Yellow and Red Zones must be controlled by permit and verified using the buddy system.
4.2 ACTIVITIES REQUIRING BREATHING APPARATUS
Air-line fed positive pressure supplied air breathing apparatus must be used for all prolonged operations where there is a risk that personnel may be exposed to hydrogen sulphide concentrations above the TLV® as a result of equipment failure or human error during the operation but not limited to or unavoidable release. This includes all of the following operations whenever such a hydrogen sulphide risk could exist:
• Breaking of containment, including swinging spectacles or inserting spades;
• Taking samples, including product quality activities where the possibility of dangerous levels of hydrogen sulphide exist;
• Confined space entry; and
• Local venting of equipment, including instruments during calibration or testing, where personnel are so close to the vent that they could be exposed to concentrations above the STEL®.
• Drilling activities on rig floor, flaring, BOP, Mud tanks, shale-shakers etc wherever the H2S levels exceed STEL®.
Positive pressure breathing apparatus must be used for these activities. Self-contained breathing apparatus (SCBA) may be used when the task involved is very short, for example sample taking. Generally air-line breathing apparatus is preferred.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 Design to avoid continuing exposure to hydrogen sulphide must be preferred to the use of breathing apparatus wherever this is practicable.
Further details of breathing apparatus requirements are given in Section 9.
4.3 SURVEYS
Where not already carried out, Group Companies must carry out surveys of operations such as sampling and venting to determine the need for breathing apparatus and any limitations on the time personnel can be present to avoid exceeding the allowable time-weighted average dose. These surveys should take into account hydrogen sulphide concentration arising from unavoidable emissions during the operation together with background emissions from such sources as leaking valve stems or local venting.
Where it is necessary for personnel to wear breathing apparatus to avoid exceeding the STEL® (5 ppm for 15 minutes) or the time-weighted average concentration (average of 1 ppm for 8 hours), Group Companies must repair or replace equipment, modify the operation to be carried out, or take other appropriate steps to avoid the need for breathing apparatus wherever this is reasonably practicable.
4.4 START UP
ADNOC Group Companies must ensure that there is independent verification of readiness before introduction or reintroduction of substances containing greater than 500 ppm hydrogen sulphide in the vapour phase after let down to atmospheric pressure. This applies both to initial commissioning and start-up and to start-up following a shutdown where breaking of containment, introduction of lockouts or overrides, or other activities have occurred which, if not properly reinstated, could compromise the ability to prevent, control or mitigate hydrogen sulphide hazards.
In this context, an independent verifier must be familiar with the plant, but must not be part of or report to the individual or team who are responsible for commissioning, starting up or reinstating the plant..
The scope of the verifier must include checking of all relevant items such as:
• Correct position of isolations, including spades;
• Reinstatement of overrides; and
• Successful completion of leak testing where relevant;
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 4.5 WORKER COMPETENCY
All personnel involved with operations involving materials containing hydrogen sulphide must be competent to perform the activities required of them.
Personnel working in Green, Yellow or Red Zones must have the level of competency for those Zones; training requirements are given in Section 7, whilst specific competency requirements are given in Section 10.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 5 MITIGATION
Where evolution of hydrogen sulphide from an accidental spill of liquid with the potential to harm people is foreseeable, then the following must be provided unless demonstrated to be not reasonably practicable:
• Secondary containment; and
• A means to limit the evolution of hydrogen sulphide, such as blanketing with foam.
Hydrogen sulphide is a reactive gas which is susceptible to explosion when mixed with air. Appropriate provisions for explosion prevention and consequence mitigation shall be taken, such as rapid ESD, and explosion protection measures.
ADNOC group companies storing solid sulphur shall determine the possibility of hydrogen sulphide being released from solid sulphur, in the case of both properly specified product and off spec production. If injurious concentrations can be generated, appropriate ventilation shall be provided as well as appropriate personal protective equipment.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 6 EVACUATION, RECOVERY & RESCUE
6.1 EMERGENCY PLANS AND PROCEDURES
The general requirements for the development and testing of emergency plans and procedures at group Company facilities are given in the ADNOC COP V5.02 Crisis and Emergency Management [Ref 3].
Where a hydrogen sulphide hazard exists, the emergency plans and procedures must take into account the nature and extent of those hazards, especially:
• Any need to alert the public or third parties of a hydrogen sulphide hazard beyond the boundary fence;
• The control of visitors, temporary workers and contractors, including contractors under the supervision of a third party, any of whom may have limited knowledge of Arabic or English;
• The need for trained rescue teams to retrieve personnel overcome by hydrogen sulphide;
• The existence and nature of Green, Yellow and Red zones and how access between them is controlled;
• The requirement for a toxic gas refuge where personnel can seek shelter whilst a gas cloud disperses (see Section 11);
• Any special requirements for personnel on air-lines in the event of either a nearby hydrogen sulphide release or other type of emergency elsewhere on the facility; and
• The time required to don emergency escape mask or breathing apparatus.
6.2 ESCAPE ROUTES IN YELLOW AND RED ZONES
All escape routes on facilities where a hydrogen sulphide hazard exists must be passable by personnel wearing self-contained breathing apparatus.
Escape routes shall be identified and marked (see COP V5-02).
For fixed installations a means of emergency communication to the control room/emergency centre shall be provided.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 7 EDUCATION & TRAINING
7.1 TRAINING FOR ALL PERSONNEL
All personnel, including temporary workers who will not always be accompanied, entering a site that has a hydrogen sulphide hazard must be trained to understand:
• Hazards of hydrogen sulphide;
• The meaning of the zone designation;
• The requirements for entering a Yellow or Red Zone;
• The understanding of warning signs related to hydrogen sulphide;
• Recognising and reporting a hydrogen sulphide leak;
• Use of personal hydrogen sulphide detectors;
• The meaning and types of alarms, both general and from personal hydrogen sulphide detectors;
• Actions to be taken in the event of an emergency;
• Escape routes and importance of moving crosswind; and
• What to do if a colleague is overcome by toxic gas.
Accompanied visitors must receive a briefing on the hazards of hydrogen sulphide, the use of emergency escape masks and escape procedure.
This training must be site specific.
This is in addition to other training that may be required for personnel to work safely.
Personnel must undergo refresher training on a yearly basis.
Training records must be maintained by the Group Company and audited annually.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 Visitors who are accompanied by a Group Company Employee at all times must be appraised of:
• Hazards of hydrogen sulphide;
• Use of personal hydrogen sulphide detectors
• The meaning and types of alarms, both general and from personal hydrogen sulphide detectors; and
• What to do in an emergency involving hydrogen sulphide.
Personnel who work at more than one site where hydrogen sulphide hazards exist, but whose duties are such that they will never enter Hydrogen Sulphide classified zones need only receive instruction in site specific issues as part of the formal site induction training and do not need to repeat the full hydrogen sulphide training at each new site. Such personnel must never enter hydrogen sulphide classified zones.
7.2 HYDROGEN SULPHIDE COMPETENCY
Valid hydrogen sulphide competency certificates are required for all personnel:
• Entering Red or Yellow Zones; and
• Working with breathing apparatus as a result of hydrogen sulphide hazards.
This is in addition to other entry requirements listed in Section 2.2.
Group Company HSE departments can, at their discretion, issue such a certificate to anyone graduating from a hydrogen sulphide competency course that includes the following elements in addition to the topics noted in Section 7.1:
• Requirements for and reasons behind facial hair restrictions;
• Requirements for entering Yellow Zones
• Requirements for entering / leaving Red Zones including register in / out procedure and interface with the Permit-To-Work system;
• Operational controls applicable for Red Zones (see Section 4);
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Document No. Date of Issue ADNOC-COPV4-10 November,2010
• Understand the buddy system and the duties of a buddy (remain alert, give alarm, keep any rescue lines clear);
• Consequences of not adhering to procedures;
• Use of PPE required by operational controls, which must include both self-contained breathing apparatus, emergency escape mask and air-line fed breathing apparatus;
• Recognition of alarms and response;
• Use of PPE in an emergency;
Before graduation and issue of a Hydrogen Sulphide Competency Certificate, personnel attending a hydrogen sulphide competency course must:
• Demonstrate understanding of the course topics;
• Demonstrate the ability to correctly don an emergency escape mask within 20 seconds and SCBA in 45 seconds.
• Demonstrate correct use of breathing apparatus; and
• Demonstrate correct operation and use of air-line fed breathing apparatus.
The time period of 20 seconds to don an emergency escape mask (pre-checked and ready for use condition), is based on tests carried out which indicate that this can readily be achieved.
Hydrogen Sulphide Competency Certificates will be valid for 12 months, after which refresher training is required.
Group Company HSE departments must audit third party hydrogen sulphide competency training providers before beginning to issue certificates and at least once per 12 months thereafter to ensure that training standards are maintained.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 7.3 WORKING WITH AIR LINES
Personnel who will be working under air line supply must be tested for fitness.
They must also demonstrate competency in:
• Understanding of air line supplies
• The importance of keeping lines free and untangled
• The importance of having a person standing by to assist in case of difficulties
• The ability to check connections and air supply
• The ability to change over connections safely
• Emergency air supply in case of air line failure
• The procedure for escape
7.4 TRAINING OF EMERGENCY RESPONSE TEAMS
Personnel in teams who will be responding to hydrogen sulphide emergencies must be trained in:
• Methods of rescuing personnel overcome by hydrogen sulphide;
• The use of equipment they may be using for emergency response;
• How to make the area safe e.g. performing isolations;
• Means of communication; and
• Treatment for personnel exposed to hydrogen sulphide.
Personnel must be able to demonstrate their competency in these subjects in a practical test before being allowed to take up their duties in an emergency response team.
This is in addition to any other training which may be required for them to fulfil their function.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 7.5 HYDROGEN SULPHIDE TRAINERS
All trainers providing hydrogen sulphide training for emergency response teams, hydrogen sulphide competency or for personnel working on a hydrogen sulphide site must be able to demonstrate working experience on sites where a hydrogen sulphide hazard exists and with the various forms of breathing apparatus and other PPE in which they will be training others.
The competency of the hydrogen sulphide trainers must be subject to audit before a Group Company can issue a Hydrogen Sulphide Competency Certificate to graduates of that trainer. Trainer qualification shall be in accordance with ANSI/ASSE Z390.1-2006, Accepted Practices For Hydrogen Sulphide (H2S) Training Programs.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 8 ENFORCEMENT
It is the responsibility of senior management to have oversight of compliance with this COP. Implementation of the requirements of this COP shall commence immediately on its issuance to the extent reasonably practical. Full implementation shall be ensured by the end of year 2013.
Personnel who do not adhere to the requirements of this COP are not only putting their own lives at risk, but also those of their colleagues, emergency service and others working on and off site. Offenders shall be subject to disciplinary action up to and including removal from site. Personnel removed from any ADNOC Group Company facility for violation of this COP shall be prohibited from entering all ADNOC Group Company facilities.
Organisations or groups carrying out design work, contractors or individual personnel who repeatedly fail to meet the requirements of this Code of Practice must not be considered for future projects, contracts or employment across the ADNOC Group of companies.
Strict compliance with the requirements of this Code of Practice must be monitored. Audits of operational sites where a hydrogen sulphide hazard exists must be carried out as often as necessary to ensure continued compliance and at a maximum interval of 12 months.
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 9 PERSONAL PROTECTIVE EQUIPMENT
9.1 GENERAL REQUIREMENTS
The sections below detail the minimum mandatory requirements for personal protective equipment.
Other restrictions may also apply, such as the ability to work safely in an area which may contain flammable gas.
9.2 EMERGENCY ESCAPE MASKS
Hydrogen sulphide at emergency levels can cause difficulty in vision and short term blindness. Escape sets must be of full-face positive pressure or positive pressure hood type with an air supply of at least 10 minutes.
The protection offered by a given respirator is contingent upon (1) the respirator user adhering to complete program requirements (such as the ones required by OSHA in 29CFR1910.134), (2) the use of NIOSH-certified respirators in their approved configuration, and (3) individual fit testing to rule out those respirators that cannot achieve a good fit on individual workers’.
Hydrogen sulphide can cause severe irritation of the eyes and temporary blindness. For this reason, hood type escape masks are preferred. Goggles may be of some use, but only if they are put on before exposure to H2S because the goggles themselves can fill with gas. Full face mask types or hood types with positive pressure air supply are freed from gas as air is passed from the storage bottle to the mask.
9.3 SELF CONTAINED BREATHING APPARATUS
Self-contained breathing apparatus (SCBA) must only be used for short tasks such as sampling, emergency response, for rescue activities and for entering and leaving Red zones. Where work activities longer than a few minutes require breathing apparatus, units must be capable of transfer to an air-line fed mode (cascade system) which must be used during the work. This is because of the finite capacity of self-contained apparatus compared to the extended capacity when air-line fed.
Sufficient SCBA sets of appropriate capacity must be ready and available at all times to allow response to identified emergencies, in addition to those sets in use by personnel working in Red Zones, or engaged in activities which require breathing apparatus. The number, location and condition of the sets must be subject to yearly audit. The appropriateness of these arrangements must be
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Document No. Date of Issue ADNOC-COPV4-10 November,2010 verified by drills or exercises as often as necessary to ensure that SCBA sets will be readily available in an emergency.
9.4 AIR-LINE FED BREATHING APPARATUS
Air-line fed positive pressure breathing apparatus must be used where there is a risk of hydrogen sulphide above the STEL® or when working in Red zones.
Where this is impractical, work may be carried out using positive pressure escape sets which are worn and ready to be quickly donned, provided that this can be demonstrated to be acceptable on an ALARP basis. Air line fed positive pressure breathing apparatus is required to be used in all cases when equipment is being opened, if the equipment contains, or has a reasonable chance of containing, hydrogen sulphide. (Use of SCBA is allowed for very
Where this is impractical, work may be carried out using positive pressure escape sets which are worn and ready to be quickly donned, provided that this can be demonstrated to be acceptable on an ALARP basis. Air line fed positive pressure breathing apparatus is required to be used in all cases when equipment is being opened, if the equipment contains, or has a reasonable chance of containing, hydrogen sulphide. (Use of SCBA is allowed for very