Readers are recommended to make good use of the concepts of "Failure Model Effects and Criticality Analysis" as discussed above. These should provide a more comprehensive study of reliability and availability of building services. The assessment methodology presented in this article is to a certain extent subjective. It is considered that a more quantitative and comprehensive study based on reliability and availability data from similar hospitals over recent years will help the analysis. Building services maintenance involves risk. Risks must be assessed before a design is fully implemented. The risks associated with building services installation have to be assessed at all stages, from concept to dismantling and disposal. This will ensure that risks are acceptable and manageable within the parameters defined by the overall cost and engineering requirements, statutory obligations and good practice.