What is the effect of leakage and room integrity on agent weight in SHS design?

• A. They do not affect agent weight.
• B. They reduce the need for agent due to infiltration.
• C. They require a different color for cylinders.
• D. Leakage and room integrity require adjusting design concentration and thus agent weight.

Answer: (D)

In SHS sizing, the amount of agent you release isn’t just about filling a room to a target concentration; it’s about a mass-balance reality where losses through leaks and air exchange reduce the concentration inside. If the room has leaks or poor sealing, air from adjacent spaces or outdoors can carry away agent or dilute it, so the final concentration inside won’t reach the intended level unless you compensate. That means you may need a higher initial design concentration or more total agent—i.e., you must adjust the design concentration to account for those losses, which directly changes the agent weight you must store and release. Conversely, a room with good integrity limits leakage, so less agent is wasted and the required weight can be lower. The key idea is that leakage and room integrity drive adjustments to the design concentration and thus the total agent weight to ensure the protected space reaches and maintains the desired concentration.