Final answer:
To determine the height at which a gravity tank should be placed above the highest sprinkler head, you need to use Bernoulli's equation and consider the pressure required for water to reach the sprinkler head.
Step-by-step explanation:
In order to determine the height at which a gravity tank should be placed above the highest sprinkler head, we need to consider the pressure required for water to reach the sprinkler head. This can be done by using Bernoulli's equation. According to Bernoulli's principle, the pressure in the tank should be higher than the pressure at the sprinkler head, accounting for the height difference between them.
For example, if the pressure at the sprinkler head is 18 mm Hg above atmospheric pressure, we can convert it to SI units (1 mm Hg = 133 Pa) and find the corresponding height of the fluid that corresponds to this gauge pressure.
By calculating the pressure difference and using the equation P = ρgh, where P is the pressure, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height difference, we can determine the required height of the gravity tank above the highest sprinkler head.