Table 4.17 Time Estimates for Using the HAZOP Study Method

DOE-HDBK-1100-2004

Table 4.17 Time Estimates for Using the HAZOP Study Method

DOCUMENTATIO

(a)

SCOPE

PREPARATION

EVALUATION

Simple/Small

System

2 to 6 days(b)

8 to 12 hours

1 to 3 days

Complex/Large

Process

2 to 4 days

1 to 4 weeks

2 to 6 weeks

(a) Primarily team leader and scribe, although others may work during this phase.

(b) Team leader and scribe only. May be shorter for experienced scribes using computer software in the HAZOP study meetings.

Source: CCPS, 1992.

4.4.5 Example Hazard and Operability Studies

Partial HAZOP studies for the example processes described in Section 4.0 are shown in

Tables 4.18 and 4.19. A complete example of a HAZOP study can be found in

Reference 10.

4.5

Failure Mode and Effects Analysis

4.5.1 Description of the Method

A FMEA is used to examine each potential failure mode of a process to determine the

effects of the failure on the system. A failure mode is the symptom, condition, or fashion

in which hardware fails. It may be identified as a loss of function, a premature function

(function without demand), an out-of-tolerance condition, or a physical characteristic,

such as a leak, observed during inspection. The effect of a failure mode is determined by

the system's response to the failure.

4.5.2 Analysis Procedure

A FMEA has three steps: (1) defining the process, (2) performing the analysis, and (3)

documenting the results. Defining the process for study and documenting the results can

be performed by a single person. The analysis itself must be performed by a team.