Recommendation 34: Harmonisation of permit to work systems

Standardisation of the permit to work system throughout the industry is neither necessary nor practicable. However, in view of the fact that there is much in common between the systems of different operators, the industry should seek to increase harmonisation, for example in the colours used for different types of permits to work and in the rules as to the period for which a permit to work remains valid (para 18.28).