Permits-To-Work

A permit-to-work system is a formal written document used to control certain types of work that are potentially hazardous. A permit-to-work is a document which specifies the work to be done and the precautions to be taken. Permits-to-work form an essential part of safe systems of work for many irregular or non-routine activities. They allow work to start only after safe procedures have been defined and they provide a clear record that all foreseeable hazards have been considered.

The following aspects should be considered with respect to Permit to Work Systems:

• Human factors;
• Management of the work permit systems;
• Poorly skilled work force;
• Unconscious and conscious incompetence;
• Objectives of the work permit system;
• Types of work permits required; and
• Contents of the work permits.

Work permit should address the following points:

• Whether staff have been sufficiently informed, instructed, trained and supervised to minimize a potential human failing during operation of the work permit system;
• Whether the work permit system includes sufficient safety information, maintenance instructions, correct PPE and equipment for use;
• Whether the work permit contains sufficient information about the type of work required (Equipment removal, excavation, hot/cold work, repairing seals, vessel entry, waste disposal, isolation);
• Whether there is sufficient provision available to fulfill the requirements of the work permit system;
• Whether the employees responsible for control of the work are identified within the work permit system and that the work is properly authorized by a responsible person;
• Whether the work permit system is managed, regularly inspected and reviewed;
• Whether all work permits are kept on file;
• Whether sufficient precautions are taken prior to initiating a work permit (isolation, draining, flushing, environmental monitoring, risk assessments, communication, time allotted for the work);
• Whether staff are aware of the type of environment they are working in during the operation of a work permit (flammable, corrosive, explosive, zones 0, 1 & 2, electricity supplies);
• Whether the person responsible for operating the plant is aware of the type of work involved and how long it is likely to take; and
• Whether the work permit system involves a formal procedure whereby the maintained plant or equipment is handed back to operation.

Major hazards could arise from the following:

• Wrong type of work permit used;
• Wrong information about work required on the work permit;
• Failure to recognize the hazards where work is carried out (e.g. flammable substances);
• Introduction of ignition source in controlled flameproof area (e.g. welding, non-spark-proof tools, non-intrinsically safe equipment used in intrinsically safe zones);
• Terms of work permit not adhered to (e.g. failure to isolate plant and/or drain lines of hazardous substances);
• Failure to hand-over plant in safe condition on completion of work/cancelling of work permit;
• Unauthorized staff performing work permit functions;
• Poor management of the work permit system; and
• Insufficient monitoring of the work permit system

Types of work permits

The type of safe work permit required is determined by the nature of the work to be performed and the hazards that must be controlled or eliminated. The range of activities and locations makes it impossible for a single type of permit to be suitable for all situations. The following types are most commonly used

Hot Work Permit

Hot work permits are used when heat or sparks are generated by work such as welding, burning, cutting, riveting, grinding, drilling, and where work involves the use of pneumatic hammers and chippers, non-explosion proof electrical equipment (lights, tools, and heaters), and internal combustion engines.

Three types of hazardous situations need to be considered when performing hot work:

(a)the presence of flammable materials in the equipment;

(b)the presence of combustible materials that burn or give off flammable vapors when heated; and

(c)the presence of flammable gas in the atmosphere, or gas entering from an adjacent area, such as sewers that have not been properly protected. (Portable detectors for combustible gases can be placed in the area to warn workers of the entry of these gases).

Confined Space Entry Permit

Confined space entry permits are used when entering any confined space such as a tank, tower, pit or sewer. The permit should be used in conjunction with a “Code of Practice” which describes all important safety aspects of the operation.

Height work permit

For all working at height a permit for “Working at Height” is required. Before erection, when scaffold materials are kept at site of erection, “Pre Erection Checklist for Scaffold” shall be carried out in prescribed form. All tubular scaffolds needs to checked and certified before being used. The medical certificate for workmen, required to work at height is required.

Electrical work permit

For all electrical isolation and energisation of electrical equipment Permit is required. To work on High Tension (HT) and Low Tension (LT) line and / or equipment is required. For Trip reset of HT and LT equipment, the clearance shall be taken on format.

Excavation work permit

Excavation permit is required for carrying out any excavation inside plant. Wherever temporary closure of road / cutting of road or blockage of main roads is required in a section or unit. The necessary approval shall be obtained in proper format for “Road or Site Closure”

General Requirements of Work Permit

All maintenance/ alteration/ construction jobs in the plant shall be carried out under valid “Permit to Work” only. Normally operating personnel do not require work permit for carrying out routine work, however in exceptional cases where they are likely to be exposed to certain risks, work permit is required. The requirement of work permit in such cases is to be decided by Safety Officer / Zone In-charge of the area/ section in-charge.

Separate permit should be issued for each job. Multiple jobs in a single permit are prohibited, except Entry to confined space and hot work inside the confined space in particular equipment. In such cases a composite permit can be issued and permit must address all the applicable aspects for both the works.

Permits and clearances shall be in printed forms, in duplicate or triplicate, depending on nature of job, serially numbered, Format Number and different colour code should be adopted for different types of permits and clearances.

Duly signed “Dos and Don’ts” for related jobs shall be attached with each permit and safety guidelines mentioned shall be complied at work site. (Committee may suggest during study period)

Depending on nature of jobs, type of permit required shall be decided.

Working at Height Permit’ shall be required for working at a height and above on a temporary structure or on a fixed structure, not meant for carrying out particular job safely.

1. For all scaffolds, pre-erection checklist in prescribed form shall be carried out before start of erection and the safety guidelines shall be complied.
2. Safety harness with lifelines secured chain pulley, hoist with a fixed structure is a must for working at height.
3. Provision of safety net should also be made.
4. All scaffolds shall be checked and certified in prescribed form before use.
5. The workmen involved in working at height should have medical certificate from a doctor.
6. Permit for working at height jobs, the following is to be ensured:

• All tools should be carried in tool kits to avoid their falling.
• Throwing or dropping of material/ equipment from height is prohibited.
• Avoid jumping from one member to another of a structure. Use proper passageway.
• Both hands should be free, while climbing the ladder. Bypassing the steps of ladder should be avoided.
• Avoid movements on overhead beam without proper fall protection.
• For details of hazards, precautions and other safety features refer standard.

All excavation permits, excavation clearance is mandatory in prescribed form. Additionally for Closure of road, permission to be taken in prescribed form and information of the same shall be circulated to all concerned in prescribed format. For Excavation Permit jobs, the following shall be ensured:

A warning or protective barricade of 1 meter height with red & white band/ self-glowing caution board should be provided around excavation site. Excavated material should be piled at least one meter away from the edge of the excavation / trench or depth of the trench whichever is more.

Provision of minimum two entries/exits should be made. Additionally in case of long trench for each 7.5 M and part thereof, there should one ladder. Safe angle of repose or proper shoring/strutting to prevent cave-in should be provided as per relevant codes and safe operating practices. Excavation clearance shall be obtained from various dept. in prescribed format before applying for excavation permit.

Permit issuing authority shall satisfy that permit conditions are met before issuing permit. It is also to be ensured that permit conditions are maintained in course of execution of the job.

Entry into confined space, where no hot work is to be carried out, may be permitted if combustible gases are below lower explosive limit. Entry with an air-supplied mask may be permitted. The oxygen level should be at least 19.5 vol. % and the concentration of toxic gases below the threshold limit.

Confined Space box-up clearance in prescribed form shall be obtained for only those spaces, where “Confined Space Entry” permit has been taken. The clearance shall be obtained in duplicate and a copy shall be returned to issuer on completion of work.

For all “Electrical isolation and energisation of equipment / line-HT” or “Electrical isolation and energisation of equipment / line-LT” permit (Inter Dept.) shall be taken, depending on the case. Similarly “Permit to work on HT line and Equipment” or “Permit to work on LT line and Equipment” shall be taken by user Dept, depending on the case. Clearance certificate shall also be taken as the case may be.

Before issuing a permit, equipment is to be inspected to ensure that the equipment/ facility is prepared for safe execution of the assigned work, the area is cleaned and all safety precautions have been adopted. Wherever necessary, ensure that equipment is isolated, drained/ depressurized, properly purged, water flushed, gas tested (including oxygen deficiency test) through portable gas meters and readings have been recorded in the permit.