Design Accidental Loads (DAL)
Design accidental loads can be prescriptive or defined by the results from a risk analysis. The four most common accidental loads which have to be designed for are
- Heat load – incident heat for a certain time period
- Blast load – pressure on a surface area as a function of time
- Mechanical impact load – impact energy on the hit area
- Environmental loads – extreme winds, waves and earth quakes
Proactima can advise on accidental loads which should be used and also prepare the DAL specification for implementation.
Recommendation to DALs is one of the main results of a QRA. For a facility in operation, the DALs determine the level of risk. The explosion exceedance graph below stems from a QRA and indicates that an in-built blast resistance of 1 barg will keep the escalation (catastrophic) frequency less than 10-4.
Explosion pressure exceedance curve is shown in the figure below.