Safety Critical Work

Safety Critical Work


What does ‘Safety Critical’ mean?

Safety critical work (SCW) is defined by the Constructing Better Health standards as:

“where the ill health of an individual may compromise their ability to undertake a task defined as safety critical, thereby posing a significant risk to the health and safety of others.”

Network Rail has their own definition of Safety Critical Work and refers to the Guided Transport System (Safety) Regulations 2006 for those working in safety critical roles in the Railways.

Risk Assessment

The employer should undertake a risk assessment of all activity to determine whether it is safety critical in nature and whether, in the event of a worker incapacity, it would likely result in a significant risk of harm to the individual worker performing the task or to others.

The fitness for SCW should not be used as a form of medical selection or disability discrimination.

“Where a job activity is defined as safety critical and an essential job requirement, the decision on reasonable adjustments for the disabled may not be met if there was a risk of harm to third parties. The risk assessment that identifies an activity as SCW should therefore distinguish between the risk of harm to the individual worker and to third parties.”

How often should Safety Critical Workers Medical Assessments be done?

Peritus Health Management recommends that a health assessment is undertaken for those working in a role which is designated as SCW:

What criteria are used?

Employees working in a Safety Critical role should not have any medical condition, or taking medical treatment likely to cause:

Health questionnaire: No evidence of ill health reported that would affect safety of self or others.
Blood pressure:
  • Must be below 180/100 in order the continue safety critical work (otherwise fail).
  • Between 160/95 and 180/100, the OH professional shall require the examinee visit their GP for advice and treatment. (Pass, with a review at 6 months),
  • Between 140/90 and 160/95 – pass – give advice on lifestyle & BHF booklet – refer to GP for advise and treatment.
  • 140/90 and below – considered normal blood pressure.
  • Individuals who are experiencing low blood pressure (90/60) due to medication should not work in safety critical roles or environments.
Hearing Hearing loss should not exceed 30dB averaged over frequencies of 0.5, 1 and 2 kHz in either ear.
No evidence of health problem which is likely to cause a sudden or unpredictable change in hearing.
Provided the standard is met without the use of a hearing aid, a hearing aid may be used to improve hearing further.
Respiratory Health FEV1% greater than 80% of predicted value. No evidence of respiratory symptoms on questionnaire.
Vision 6/9 in better or 6/12 in the other eye. Also uncorrected acuity must be at least 3/60.
Colour perception Achieves a pass, red/green using ishihara test plates.
Mental Health No evidence of mental ill health which is likely to impact on ability and safety to self and others. Normal Hospital Anxiety and Depression Score – fit.
Urinalysis Glucose – negative
Protein – negative
Blood – negative
Any positive results should be investigated appropriately. If the investigations indicate that the positive result does indicate an underlying disease and the person is well then this is acceptable.
Mobility and co-ordination assessment No evidence/reporting of musculo-skeletal or neurological disorder that could affect safety of self or others.
Drug or alcohol screening Pass test result. No evidence of over the counter or prescribed medication likely to cause symptoms. NDT Kit test contents are listed on the separate report form but may contain a combination of: Amphetamine, Benzodiazepines, Barbiturates, Morphine, Cannabis, Cocaine, EDDP – methadone metabolite, Ketamine, Methadone, Metamphetamine, Opiates, Phenclyclidene and Propoxyphene.

Peritus Health Management understands that the hardest part of any occupational health assessment is the logistics of arranging the appointments, getting the individuals to attend and covering the work. We therefore undertake ‘Safety Critical Plus’ assessments which means that the assessment also includes assessment for noise-induced hearing loss, respiratory health, hand-arm vibration tier 2 and skin surveillance for health surveillance purposes. This saves you time arranging for additional appointments. If you don’t require health surveillance, please let us know as this will affect the recalls we put in place.

How long does it take?

This depends on your health and safety risks and whether you wish to meet your health surveillance legal obligations at the same time. Consider the options below:

Safety Critical Safety Critical Plus
Questionnaire Basic fitness for work questions Includes all questions required to support hearing, respiratory, hand arm vibration level 2 and skin surveillance.
Blood pressure Included Included
Hearing Test 0.5, 1 and 2khz only Full frequencies to support health surveillance and differentiate between noise-induced hearing loss and other forms of hearing loss.
Otoscopic examination
Respiratory test Greater than 80% FEV1 achieved British Thoracic Society and Association for Respiratory Technology and Physiology’s standards of spirometry to support early detection of disease.
Vision 6/9 in better or 6/12 in the other eye. Also uncorrected acuity must be at least 3/60.

Colour perception – pass in red/green.

6/9 in better or 6/12 in the other eye. Also uncorrected acuity must be at least 3/60.
Depth perception
Field of vision
Colour perception – pass in red/green.
Mental Health Questionnaire Questionnaire
Urinalysis Glucose – negative
Protein – negative
Blood – negative
Any positive results should be investigated appropriately. If the investigations indicate that the positive result does indicate an underlying disease and the person is well then this is acceptable.
Glucose – negative
Protein – negative
Blood – negative
Any positive results should be investigated appropriately. If the investigations indicate that the positive result does indicate an underlying disease and the person is well then this is acceptable.
Mobility and co-ordination No evidence/reporting of musculo-skeletal or neurological disorder that could affect safety of self or others.
Truck, leg and neck movement check.
No evidence/reporting of musculo-skeletal or neurological disorder that could affect safety of self or others.
Truck, leg and neck movement check
Hand grip strength check
Health education Interpretation and explanation of results of all tests. Interpretation and explanation of results of all tests.
Supporting health surveillance for:

  • noise risks
  • respiratory risks
  • HAVS risks
  • skins risks
Time Taken 45 minutes 75 minutes
Drugs and Alcohol screening (optional) Pass test result. No evidence of over the counter or prescribed medication likely to cause symptoms. NDT Kit test contents are listed on the separate report form but may contain a combination of popular drugs taken for recreational purposes.
Chain of custody testing may be required as part of this test and incurs additional charges.
Pass test result. No evidence of over the counter or prescribed medication likely to cause symptoms. NDT Kit test contents are listed on the separate report form but may contain a combination of popular drugs taken for recreational purposes
Chain of custody testing may be required as part of this test and incurs additional charges.

Constructing Better Health Standards are best practice standards and are not legally binding. We strongly recommend that where an employee’s health does not meet these standards, an individual functional assessment/risk assessment is undertaken to determine whether they are fit to work in the specific duties for which they are employed.

Where reasonable adjustments cannot be made to ensure the health, safety and welfare of the employee or others, we recommend that you seek advice from your solicitor before any action is taken regarding the individual’s employment.

Employees driving LGV, HGV, PSV, or other vehicle which requires specific licensing by the DVLA, are subject to the DVLA’s Medical Standards for Fitness to Drive guidance which is legally binding. Those not meeting Safety Critical Workers Medical Assessment should have a further assessment with an Occupational Health Specialist before allowing them to drive such vehicles.

Peritus Health Management works to CBH standards and is accredited by SEQOHS for working in the Construction Sector.

Want to Find Out More?

For more information about our health services, contact us.


Published date: 19th February 2018

Last revision: 27th September 2019

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