The pressure:bursts relationship

The pressure:bursts relationship – how burst frequency varies with pressure – was not quantified until some 10 years after the 1999 UARL equation was published. The 1999 UARL equation assumes that burst frequencies on mains and services are fixed at the average values for 50 metres pressure. UARL with SCF  introduces pressure:burst frequency relationships in which UARL burst frequencies reduce slightly at less than 50m pressure, and increase rapidly above 50m pressure.