City Guilds Model Questions Vol1 2019 Engineering Question 22
Practice objective / multiple choice question 22 from the 2019 City Guilds Model Questions Vol1 Engineering examination.
In a workshop a flammable‑liquid spill creates a vapor cloud that initially raises the concentration to \(2\)% (by volume). The room volume is \(120\) m³ and the ventilation provides \(12\) air changes per hour. (a) Assuming perfect mixing and first‑order decay, calculate the minimum time required for the concentration to fall to \(10\)% of the lower explosive limit (LEL), where the LEL for the liquid is \(1.5\)% by volume. (b) A Class B fire extinguisher contains \(2\) kg of CO₂; each kilogram can suppress \(0.8\) m³ of vapor. Determine whether this extinguisher is sufficient to extinguish the fire once the concentration reaches the safe level.
Answer Options
About This Question
This is City Guilds Model Questions Vol1 2019 Engineering Question 22. It is one of the objective questions from the 2019 City Guilds Model Questions Vol1 Engineering examination.
Difficulty level: Medium .
Master the Exam!
You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.