Preliminary Hazard Analysis (PHA)

In the case of MIL-STD-882 System Safety Programs, the Preliminary Hazard Analysis is the first analysis performed. The Preliminary Hazard Analysis identifies safety-critical areas, provides an initial assessment of hazards, and identifies requisite hazard controls and follow-on actions.

The PHA is used to obtain an initial risk assessment of the system hazards. It is based on best available data, including accident/incident data, from similar systems and other lessons learned. Hazards, associated with the proposed design or function, are evaluated for hazard severity, hazard probability, and operational constraints. Safety provisions and alternatives, needed to eliminate hazards or to reduce their associated risk to an acceptable level are included in the PHA.

To this day, many contracts erroneously call for a PHA as a final deliverable.

There are very few useful published guidelines for producing a PHA, which is the precursor to all subsequent safety analyses. So, beyond "brainstorming", how should the process be conducted? Read on.

HCRQ can teach you how to perform better, faster PHAs using Optimal Hazard Identification (OHI) either at our system safety course or ar our focussed webinar. We have been tasked, on more than a few occasions, to coordinate PHA sessions even in cases where we know very little about the system being developed. This is a testimony to the effectiveness of the OHI process. Get ready to save money. Remember how costly these multi-disciplinary meetings are?

The PHA is not the only hazard identification technique. In the case of SAE ARP4761, Functional Hazard Assessment (FHA) is the first analysis performed (by the way FHA does not equal PHA). Some people use HAZOP or, believe it or not, FMEA techniques for this purpose.

If you would like to purchase a PHA Data Item Description (DID) from us click here (you won't find a DID of this caliber elsewhere).