This document is for the use of employees and its subcontractors, who are responsible in operations of instruments using ionising radiation. This document covers specific instructions on how to safely perform radiography related task.
Please note that this method is general and more specific procedure should be adopted when doing any activity related to radiography works.
Definitions
- Radiation – for the purposes of this document, deemed to cover ionizing radiation’s occurring by natural decay of radioisotopes (nuclides) and/or x-rays as produced by electrical means from portable equipment.
- Base – means company property where equipment is stored, maintained or the like.
- Personnel – shall cover Company management, employees and any contractors.
- Site – means any area where services are offered to a Client on their property.
- Sources – means both gamma ray and/or x-ray capable of ionising radiation production.
- Ionization – means the process in which a charge, positive or negative, is gained by a neutral atom or molecule.
Radiological Protection
All persons will be categorized under the following descriptions for such duties involved where the use of ionizing radiation’s are involved. Maximum Permissible Dose rates:
The limit for the effective dose to a worker is an average of 20 millisieverts (mSv) per year.
The maximum permissible dose rates for the personnel categories shall be as follows:
| mSv/yr (Rem/yr) mSv/13wks(Rem/13 wks) |
| 1. RSO’s 20 (2) 15 (1.5) |
| 2. Authorized persons 20 (2) 15 (1.5) |
| 3. Classified persons 20 (2) 15 (1.5) |
| 4. Non-classified persons 10 (1) 7.5 (.75) |
Radiation Safety Officer (RSO)
The Company shall appoint, in writing, one or more suitably qualified employees as Radiation Safety Officer.
They will be responsible for the supervision of all aspects of work involving the control, storage, use and transport of radioactive sources and use of x-ray equipment.
Duties also include overseeing safe working practices, capability of dealing with emergencies, investigation and reporting of incidents.
They shall be subject to medical and monitoring requirements. Name(s), location and telephone contact numbers shall be prominently displayed at base office and all sites where work involves the use of ionizing radiations.
Authorized Persons
The Company shall appoint suitably qualified employees as Authorized Persons. Such persons will be trained and approved in writing to internationally recognized standards and shall be capable of demonstrating and undertaking the following specific duties:
- Use and control of ionizing radiation’s, x-ray and/or gamma ray sources.
- establishing barriers for the protection of personnel where ionizing radiation’s are present.
- Use of radiation monitoring equipment.
- Control of sources, including safety operations involving RSO as and when necessary.
- Investigation and reporting of incidents.
- They shall be subject to medical and monitoring requirements.
Classified Person
The Company shall appoint suitably trained employees whose work causes same to be within the proximity (controlled area) of ionizing radiation’s, normally assistants or trainees under guidance of Authorized Person.
Such person’s duties require knowledge of the operation for the safe termination of any operational exposure of ionizing radiation and use of radiation monitoring equipment to observe barrier parameters. He will be subject to medical and monitoring requirements.
He is not permitted to undertake any other duties involving ionizing radiation’s unless so authorized in writing by the Company.
Non-classified Person
Such persons not classified in accordance with above requirements i.e. general public, contract personnel, and/or others. They are not permitted to be involved in work or passage where ionizing radiation’s are present, for this reason same are excluded from radiation areas where specific barriers and warning signs are erected for their protection and radiation dose rate exceeds 7.5 Sv/hr (0.75mr/hr).
Radiation Monitoring
All classified personnel shall be provided with a monitoring film badge/thermo luminescent dosimeter as supplied by an approved organization (e.g. HPA UK). The badge must be worn on the body outside clothing and shall be replaced on a four weekly basis with the TLD/film being returned to the laboratory for assessment. The classified person is responsible for the proper use and safe keeping of his badge and film/TLD plate and would be subject to action by the Company for failure to return same to base office, or loss, or damage.
Incident reporting
Any incident involving ionising radiation where a dose rate in excess of that permitted is suspected must be reported immediately with full details to the RSO who will investigate and decide upon action to be taken.
Sealed Sources
The company has only gamma ray exposure equipment of the remote control type and each projector has a unique number to facilitate record keeping in respect of movement, location and for maintenance purposes. The sealed source also has a unique number for record purposes.
Control of sealed sources
An accurate accounting system shall be maintained for individual sources.
Each source record shall include the serial number, receipt date, decay chart, test report, projector or transit container used, daily location and disposal date including method and documentation.
Daily movement of sealed sources shall be recorded in the store/site log book and shall be signed in and out by the responsible authorised person.
Loss of sealed source
The purpose of accurate record keeping for sealed sources is to prevent loss and to provide detailed information of last known whereabouts should loss occur.
It is the express duty of all personnel to notify the RSO immediately if there are any grounds for believing that a source has been lost or mislaid.
The RSO shall investigate circumstances and then initiate a search, keeping those with a need to know informed at all times.
Operational Procedure
All operations carried out by authorized personnel involving ionizing radiations are strictly controlled in accordance with the requirements of this document and the Company’s Safety Policy.
All equipment supplied by the Company is of modern technical specification and having a unique number to facilitate accurate record keeping for location calibration and maintenance purposes.
Radiation survey meters are provided with current calibration certificates to ensure that the dose rate at the barrier of any radiation area does not exceed 7.5Sv/hr (0.75mR/hr) and that when using gamma sources that the source is returned safely to it’s container after each exposure.
Collimators are provided for use with gamma sources to reduce radiation levels. To prevent access to any radiation area, warning signs, barriers, flashing lights are posted to warn of the hazard.
Personnel are issued with monitoring film badge/thermo luminescent dosimeter, audible alarm and quartz fibre dosimeter, which gives reasonably accurate instant assessment of the cumulative dose received.
The techniques, equipment and personnel training have been developed over the years on work sites throughout the world and by experience the selection of both qualified personnel and proven equipment together with the requirements of this document serve to afford the safest possible working environment for authorised/classified and non-classified personnel alike together with a sound, practical method of working with ionizing radiation’s.
Site Radiography Method
Upon instruction to proceed to job site for work involving the use of ionizing radiations, the authorized person will adopt the following procedures:
Mobilization
- Establish method required, whether x-ray or gamma ray, and rules governing same for subject work or site.
- Select most suitable source available in reference to work to be undertaken. If gamma radiography then refer to and take copy of relevant decay chart for the source chosen.
- Obtain from stores all necessary equipment to fulfill the work safely and ensure all items are fully operable.
- Obtain all necessary safety and monitoring equipment, together with calibration certificates where applicable.
- For gamma radiography, check and monitor source prior to removal from storage, then enduring projector/container locked with key removed, log the destination of same at work site together with time removed from storage and authorized persons signature then proceed to job site.
Source Movement Control
A log shall be maintained at each storage facility to show the disposition of all sources normally assigned. All sources shall be logged out and into the store on single line entries containing the following information:
- Date and time out of store.
- Destination of source.
- Signature of person removing source.
- Date and time of return.
- Signature of person returning source
Job site
- Report to the responsible person on arrival at the job site and briefly explain the requirements for safe operational area highlighting the hazards associated with ionizing radiation.
- Set barriers, warning signs and flashing lights (if applicable) around proposed area of exposure.
- Perform trial exposure to monitor and adjust barriers if necessary.
- For gamma radiography, the source shall be monitored both during exposure and retraction to ensure accurate location into collimator and safe return to projector
- As work progresses, barriers must be monitored particularly for any change in location or in orientation of the source.
- Should any emergency arise involving ionizing radiation then the authorised person in charge shall observe all steps given in the Radiation Emergency Procedure G-3004.
- On completion of work, remove all barriers, signs and lights; check equipment lists and leaving job site tidy proceed to base.
Demobilization
- Monitor gamma projector prior to returning to its storage then return same with key to store man or other suitable keeping, logging all details.
- Return all equipment to stores reporting on any loss or malfunction in writing.
- Only authorized company personnel shall transport sealed sources.
Storage
Stores shall have the following characteristics which shall be in accordance with the applicable Federal and Project regulations.
- Protection of contents from the effects of weather.
- Resistance to fire sufficient to minimize loss of shielding.
- Storage facility shall have warning signs including both the trefoil radioactive warning and written in both English and Arabic on all sides this room shall have proper ventilation
- Maximum radiation level at the external surface of 2.5mSv/hr when fully stored with all assigned radioactive sources.
- The storage shall be contained in a security fence where the radiation level shall not exceed 1.0mSv/hr
- Both the storage facility and the fencing shall be individually secured by padlock.