What is the minimum water flow rate at the point of flame impingement for a highway tanker or railway tank car?

What is the minimum water flow rate at the point of flame impingement for a highway tanker or railway tank car?

• A. 250
• B. 750
• C. 500
• D. 1000

Answer: (C)

Cooling a burning tank car requires enough water to absorb heat quickly where flames are striking the shell. At the point of flame impingement, heat transfer to the outer surface is at its peak, so delivering a sufficient water flow helps keep the tank shell temperatures below dangerous levels and reduces the risk of structural failure or a BLEVE. The minimum practical flow to achieve this cooling is five hundred gallons per minute, which provides enough mass of water to absorb the intense heat. Lower flows may not prevent overheating, while higher flows are useful for larger fires or harsher conditions, but five hundred gpm is the baseline.

Cooling a burning tank car requires enough water to absorb heat quickly where flames are striking the shell. At the point of flame impingement, heat transfer to the outer surface is at its peak, so delivering a sufficient water flow helps keep the tank shell temperatures below dangerous levels and reduces the risk of structural failure or a BLEVE. The minimum practical flow to achieve this cooling is five hundred gallons per minute, which provides enough mass of water to absorb the intense heat. Lower flows may not prevent overheating, while higher flows are useful for larger fires or harsher conditions, but five hundred gpm is the baseline.