what you imagine was the incident including any hazards existing prior to or during the incident.

Part (a) A gas scrubber on an oilrig discharged gas periodically such that an accumulation of hydrocarbon gas nearby had occurred. A contractor welder was dispatched to a job immediately adjacent to the area and it being a shift change and personnel unavailable temporarily, the welder decided to commence welding. As a consequence, an incident occurred.

Describe briefly:
(i) what you imagine was the incident including any hazards existing prior to or during the incident
(ii) the consequences of the incident on personnel, equipment or process
(iii) emergency procedures put into practice during and immediately after the incident
(iv) indications of possible cause(s) of the incident (include any breaches of safety procedures (permits to work, etc.) statutory systems, codes of practice and company safety rules that led to the incident and any other causes or contributing circumstances
(v) recommendations/suggestions that would reduce the possibility of a repetition of the incident.
(This is based on a real incident.)

(b) Describe briefly (as in (i) to (v) of part (a)) a hazardous incident with which you are familiar.

Question 2.

(a) Distinguish between a Hazard and Operability Study (HAZOP) and Hazard Analysis (HAZAN).
(b) Explain briefly the quantities shown in the equations used for hazard analysis H = D . fdt = D x 1/2F . T (if F . T << 1).

(c) State the units of H and D and hence determine the units of fdt if any.

(d) FIGURE 1 shows an external intermediate vessel which receives a continuous mixture of hydrocarbon liquid and small variable amounts of water. The water must be separated by settlement into the sump to prevent contamination of a later hydrocarbon processing stage. The sump should be drained every 4 hours by an operator. The operation is facilitated by a sight glass and high level alarm. Under normal conditions the sump would fill in approximately 10 hours.