Human Factors, Safety Precautions and Engineering Standards
October 1, 2026
8 min read
DITEC Experts, Radiation Protection Team, ALDuha Institute for Training and Environmental Consulting
The Regulation assumes people will make mistakes
Three articles build one idea. Article 63 acknowledges human error and requires design that reduces and detects it. Article 65 requires precautionary layers because error will occur anyway. Article 66 requires those layers to be built to an engineering standard that is kept current.
Article 63: prevent, detect, intervene
The text first requires applying the appropriate principles that take account of operators' capabilities in equipment design and in applying operating procedures. It then requires three sequential things: reducing as far as possible the probability of human error, providing the means necessary to detect it, and facilitating the intervention mechanism in emergencies.
That ordering is an engineering one, not a moral one. The text does not say train workers so they do not err; it says design so that error is hard, provide what detects it if it occurs, and make intervention easy afterwards.
In practice: a procedure that relies solely on an operator remembering a critical step is a procedure short of layers. The human step is not abolished. The article requires something alongside it that reveals an omission: an alarm, an interlock, a signed checklist. The radiation survey after each exposure remains the operator's duty, and it remains the facility's duty to add something that flags it if it is not done.
Article 65: precaution scaled to probability
The licensee undertakes to apply a precautionary system for protection and safety, proportionate to the magnitude of possible or latent exposures and their probabilities. Both terms of the equation are stated together in the text: magnitude and probability.
Precision matters here. A low-activity source handled daily may warrant more detailed operational and procedural controls than a high-activity source rarely handled, provided the engineered protection for the higher-activity source never falls below what its category requires, since the magnitude of possible harm does not change with frequency of use. Probability raises controls; it does not lower the floor.
The three aims describe a full cycle: prevent accidents, mitigate their consequences if they occur, and return sources to safe conditions afterwards. The third is the one emergency plans forget. Many end at evacuating the area, while the text asks for a step beyond it: returning the source to a safe condition.
The word latent deserves attention. A latent exposure is one that has not occurred and may occur through failure or error, so precaution is built on what could happen rather than on what has. The concept corresponding to a precautionary system in IAEA literature is defence in depth: successive independent layers that do not depend on one another, which is broader than mere redundancy of components.
Article 66: the standard covers the whole life
The text lists stages that leave nothing out: siting, design, construction, assembly, preparation for operation, operation, maintenance, and permanent shutdown.
The last is the surprise. Permanent shutdown sits inside the article, so taking a facility or device out of service at the end of its life is held to the same engineering standard as building it. A facility planning a new device without knowing how it will end has deferred an obligation, not escaped it.
The three specifications of Article 66
What each one adds
- 1. Engineering instructions supported by documented administrative and organisational systems ensuring that protection and safety requirements are implemented throughout the life of the sources. The link between engineering and management is written, not inferred.
- 2. Adequate safety margins in design and construction, such as to ensure reliable performance under normal operating conditions, with due regard to quality and inspectability, prevention and mitigation of accidents, and limiting future exposures. Inspectability is a design condition: what cannot be inspected cannot be relied on.
- 3. Taking account of scientific and technical developments and research results. This is the article's most consequential requirement over the long term: a standard adequate on the day of construction does not stay adequate by the mere passage of time.
Questions this article gets asked
What is the precautionary system in Article 65?
Successive, independent protective layers, so that no single failure or error alone causes exposure and no single cause collapses them all. The text scales them in proportion to the magnitude of possible or latent exposures and their probabilities together.
Does Article 66 cover permanent shutdown?
Yes, expressly: permanent shutdown is listed among the stages subject to the engineering standards. Disposal of the disused source itself is not the subject of this article; it is governed elsewhere in the Regulation, by the decisions issued under it, and by your licence conditions, so meeting the engineering standard does not substitute for them.
Taking account of scientific developments: does that mean annual updates?
The text sets no interval. It requires the facility to have a way of noticing changes in standards and recommendations and deciding what they mean for it, rather than assuming the construction-era standard holds forever.
Who must take account of operator capabilities: the manufacturer or the licensee?
Article 63 addresses the licensee: applying the appropriate principles in equipment design and in applying operating procedures. Selecting equipment, writing procedures and operating them are the licensee's responsibility, whoever manufactured the device.
How the Institute can help
Articles 63, 65 and 66 describe a complete safety philosophy: assume the error, build layers scaled to probability, and make those layers inspectable while keeping their standard current.
Licensed training covering operating procedures and emergency response, and advisory support in reviewing procedures against the prevent, detect and intervene sequence that Article 63 sets out.
Scope of what the Institute does: licensed training and consulting. Field radiation surveys are carried out through specialist partners. The Institute does not carry out laboratory analysis, instrument calibration or equipment testing.
This article is an explanatory overview based on the official Arabic text of Executive Regulation No. (4) of 2003. It is not legal advice and does not replace your licence conditions or review by the regulator. English quotations are unofficial translations; the Arabic text prevails.