Question

drain pipes from clothes washers should have a direct connection to a plumbing stack go into a standpipe not have a trap in the standpipe for fear of collecting debris and clogging have standpipes that discharge into the trap arm of a laundry tub have standpipes that are less than 18 inches long question 20 soil pipes carry liquid and solid waste from a toilet carry liquid wastes only in a horizontal plane carry liquid wastes only in a vertical plane carry air only on horizontal runs carry solid and liquid waste on vertical runs only

Explanation:

1. For the first question about drain - pipes from clothes washers: It is standard practice for clothes washer drain pipes to go into a standpipe. A direct connection to a plumbing stack can cause issues, and standpipes typically have traps to prevent sewer gas from entering the home. Standpipes discharging into the trap arm of a laundry tub is not the norm, and there is no such strict length limit of less than 18 inches for standpipes.
2. For the second question about soil pipes: Soil pipes carry both liquid and solid waste from a toilet. They are not limited to horizontal or vertical planes for liquid waste only, nor do they carry air on horizontal runs or carry solid and liquid waste only on vertical runs.

Answer:

1. go into a standpipe
2. carry liquid and solid waste from a toilet