Compartment pressurisation demonstration: the spread sheet works out the total air leakage from the compartment for a particular level of applied pressurisation. Bear in mind that all BS 5588 systems have an ‘open door’ requirement in addition to the static pressurisation shown, that can add to the pressurisation demand. Specialist advice should be sought for any implementation of results. In pressurisation, too much pressure can be as much a problem as too little, and allowances in all areas of the design need to be included.