Question

pressure loss due to friction
is zero when there is no water flowing
cannot exceed 20 psi
is independent of pipe length
is independent of pipe diameter
is independent of pipe wall smoothness
question 26
to meet common standards, we have to inspect all of the following except
foundation irrigation systems
water heating equipment
normal operating controls for water heaters
automatic safety controls for water heaters
chimneys and flues and vents for water heaters

Explanation:

1. For the first question about pressure - loss due to friction: Friction in a pipe occurs when there is relative motion between the fluid (water) and the pipe walls. When there is no water flowing, there is no relative motion, so friction is zero. Pressure loss due to friction is related to pipe length, diameter, and wall smoothness, and there is no fixed upper - limit of 20 psi.
2. For the second question about inspections: Foundation irrigation systems are not directly related to the common standards for water - heater inspections. Water - heater inspections typically involve checking the water - heating equipment, its operating and safety controls, and related ventilation components.

Answer:

1. is zero when there is no water flowing
2. foundation irrigation systems