What does HAZOP stand for in chemical engineering?

Hazard and Operability Study

True or False: The HAZOP guide word 'MORE' indicates complete negation of design intent.

False. 'MORE' indicates quantitative increase, while 'NO/NOT' indicates complete negation.

Fill in the blank: Risk = _____ × Consequence

Frequency

Which HAZOP guide word represents the logical opposite of intent?
A) PART OF
B) REVERSE
C) AS WELL AS
D) OTHER THAN

B) REVERSE

What does PFD stand for in LOPA analysis?

Probability of Failure on Demand

A safety system has PFD = 10⁻³. What SIL rating does this represent?

SIL 2

True or False: In fault tree analysis, an AND gate output occurs if any input occurs.

False. AND gate output occurs only if ALL inputs occur simultaneously.

What happens when pressurized liquid is released and undergoes partial vaporization?

Flashing occurs, creating a two-phase vapor-liquid mixture

Fill in the blank: The discharge coefficient Cd for sharp-edged orifice is typically _____.

0.61-0.62

For choked flow conditions, downstream pressure must be _____ than critical pressure ratio.

Lower

Which inherent safety principle should be applied first?
A) Substitute
B) Minimize
C) Moderate
D) Simplify

B) Minimize

What does BLEVE stand for?

Boiling Liquid Expanding Vapor Explosion

True or False: Deflagration is a supersonic combustion wave.

False. Deflagration is subsonic; detonation is supersonic.

If initiating event frequency = 0.2/year and PFDs = 0.1, 0.01, what is scenario frequency?

2 × 10⁻⁴ events/year

Fill in the blank: LOC stands for Limiting _____ Concentration.

Oxygen

A mixture contains 30% methane (LFL=5%) and 70% propane (LFL=2.1%). Calculate mixture LFL using Le Chatelier's rule.

2.8%

What atmospheric stability class represents neutral conditions?
A) Class A
B) Class C
C) Class D
D) Class F

C) Class D

True or False: Dense gases follow standard Gaussian dispersion patterns.

False. Dense gases require specialized models like SLAB or DEGADIS.

In pool fire radiation, what does the radiative fraction χrad typically range for hydrocarbons?

0.2 to 0.4

What is the TNT blast energy value used in equivalency calculations?

4.68 × 10⁶ J/kg

Fill in the blank: ERPG-3 represents _____ effects exposure level.

Life-threatening