Special Hazard Systems

7 - 11 questions on the Fire Protection PE Exam

Special Hazard Systems cover the non-water suppression agents — clean agents, CO₂, inert gases, foam and dry chemical — and account for about 7 to 11 questions. Codes such as NFPA 2001, NFPA 12 and NFPA 11 govern them. Section 7 of the Fire Protection PE Textbook organizes the agents, their design criteria and their key calculations.

What the Textbook Covers: Special Hazard Systems

The NCEES specification lists four sub-areas:

System Selection

CO2, inert gas, clean agent, wet and dry chemical, foam, oxygen reduction, and ignitable-liquid drainage floor assemblies.

Design Criteria

System controls, enclosure integrity, agent storage, system parameters and testing.

Principal Components

Valves, discharge devices (nozzles) and support arrangements.

Calculations

Agent quantity, design concentration, lower flammable limit (LFL), and flow rates.

A Taste: Clean Agent Quantity

Clean agent quantity depends on the protected volume, the required design concentration and the agent’s specific vapor volume, which itself varies with temperature. The classic NFPA 2001 form is W = (V/s) × [C / (100 − C)], where C is the design concentration in percent and s is the agent’s specific volume. Get the concentration or the temperature correction wrong and the whole answer shifts — exactly what NCEES tests.

The textbook lays out the agent families side by side and works the concentration and quantity calculations step by step.

This is only a preview. The full explanation, diagrams, worked examples and practice problems are in the Fire Protection PE Textbook.

Get the Full Picture

Special hazard questions hinge on a few key formulas. Practice them with the full study system:

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