WFSM 2025/2026 VOL 3 SELF-TEST
QUESTIONS PART 2 WITH COMPLETE
SOLUTIONS
What are some of the dangers associated with thawing frozen pipe with hot water and
rags? - ANSWER-Scalding, slipping, and water damage.
What precautions must you take when you are thawing pipes with a torch? - ANSWER-
Isolate the area with a heat shield, ensure adequate ventilation, and have a fire
extinguisher nearby.
Before attaching electrical thawer cables, what should you do to prepare the pipe? -
ANSWER-Thoroughly clean the contact area by sanding pipe with emery cloth.
What could happen if electric thawer cable connections are not tight? - ANSWER-It
could cause arcing, which will burn a hole into the pipe.
What types of water main breaks would a full-circle clamp repair? - ANSWER-Holes,
splits, and full breaks.
What sizes are full-circle clamps available in circumference and length? - ANSWER-1¼
to 24" and 6 to 36" long.
What are the construction variances of a full-circle clamps? - ANSWER-0.4 to 0.8".
How do you tighten the bolts on a full-circle clamp? - ANSWER-Evenly tighten bolts
working from center outward.
How do you make a permanent repair on steel pipe? - ANSWER-Disconnect pipe,
remove damaged pipe, and reinstall new sections with a union in between.
What fittings are used to connect two pieces of pipe when repairing copper? -
ANSWER-Use a slip coupling.
What are the four steps involved in the disinfection of a main? - ANSWER-Flushing,
dosing, flushing again, and testing.
What are the three forms of chlorine? - ANSWER-gas, liquid, solid
What is the accepted contact time for disinfecting a main? - ANSWER-Usually 24 hours
at 50 ppm chlorine residual.
, List the components of a wastewater collection system. - ANSWER-Building sewer,
lateral and branch sewers, main sewers, trunk sewers, interceptor sewers, manholes,
lift stations, wastewater treatment plants, outlet (outfall) sewers.
Which part of the collection system connects the building drain to the sewer main? -
ANSWER-The building sewer
What is the purpose of the sewer main? - ANSWER-To convey wastes received from
lateral and branch sewers to trunk sewers.
What is the purpose of an industrial sewer? - ANSWER-To convey highly polluted
wastewater to a separate "industrial treatment plant," where all harmful chemicals are
removed or neutralized.
Where does the building sewer start? - ANSWER-2-10' from a building foundation.
What can you do if no provision has been made for connecting a building sewer to the
sewer main? - ANSWER-Remove a section of the sewer main and install a precast
fitting, or tap into the sewer main and make a fitting called a thimble.
Where do you start laying pipe for the house sewer? - ANSWER-At the precast fitting or
the thimble, working towards the building drain.
Why must you remove the soil from under each hub when you lay the pipe for the house
sewer? - ANSWER-So that the entire length of the pipe lays on a firm bed, not just the
bell ends.
What part of the collection system pumps wastewater to a higher level? - ANSWER-
Sewage lift stations
Where does the building drain end? - ANSWER-2' outside the building wall or
foundation.
Why are manholes placed in a sanitary sewer system? - ANSWER-To allow
maintenance personnel and their equipment access to the collection system.
What are the three primary factors that affect the proper operation of a sewer main? -
ANSWER-Proper size, slope, and lack of obstructions.
What is the operational effect of oversizing a sewer main? - ANSWER-The wastewater
will have a tendency to leave solids behind.
What is the fall of a 3" building sewer? - ANSWER-Not less than 1/4" per foot.
What is the ideal flow rate of wastewater in a sewer main? - ANSWER-2 fps
QUESTIONS PART 2 WITH COMPLETE
SOLUTIONS
What are some of the dangers associated with thawing frozen pipe with hot water and
rags? - ANSWER-Scalding, slipping, and water damage.
What precautions must you take when you are thawing pipes with a torch? - ANSWER-
Isolate the area with a heat shield, ensure adequate ventilation, and have a fire
extinguisher nearby.
Before attaching electrical thawer cables, what should you do to prepare the pipe? -
ANSWER-Thoroughly clean the contact area by sanding pipe with emery cloth.
What could happen if electric thawer cable connections are not tight? - ANSWER-It
could cause arcing, which will burn a hole into the pipe.
What types of water main breaks would a full-circle clamp repair? - ANSWER-Holes,
splits, and full breaks.
What sizes are full-circle clamps available in circumference and length? - ANSWER-1¼
to 24" and 6 to 36" long.
What are the construction variances of a full-circle clamps? - ANSWER-0.4 to 0.8".
How do you tighten the bolts on a full-circle clamp? - ANSWER-Evenly tighten bolts
working from center outward.
How do you make a permanent repair on steel pipe? - ANSWER-Disconnect pipe,
remove damaged pipe, and reinstall new sections with a union in between.
What fittings are used to connect two pieces of pipe when repairing copper? -
ANSWER-Use a slip coupling.
What are the four steps involved in the disinfection of a main? - ANSWER-Flushing,
dosing, flushing again, and testing.
What are the three forms of chlorine? - ANSWER-gas, liquid, solid
What is the accepted contact time for disinfecting a main? - ANSWER-Usually 24 hours
at 50 ppm chlorine residual.
, List the components of a wastewater collection system. - ANSWER-Building sewer,
lateral and branch sewers, main sewers, trunk sewers, interceptor sewers, manholes,
lift stations, wastewater treatment plants, outlet (outfall) sewers.
Which part of the collection system connects the building drain to the sewer main? -
ANSWER-The building sewer
What is the purpose of the sewer main? - ANSWER-To convey wastes received from
lateral and branch sewers to trunk sewers.
What is the purpose of an industrial sewer? - ANSWER-To convey highly polluted
wastewater to a separate "industrial treatment plant," where all harmful chemicals are
removed or neutralized.
Where does the building sewer start? - ANSWER-2-10' from a building foundation.
What can you do if no provision has been made for connecting a building sewer to the
sewer main? - ANSWER-Remove a section of the sewer main and install a precast
fitting, or tap into the sewer main and make a fitting called a thimble.
Where do you start laying pipe for the house sewer? - ANSWER-At the precast fitting or
the thimble, working towards the building drain.
Why must you remove the soil from under each hub when you lay the pipe for the house
sewer? - ANSWER-So that the entire length of the pipe lays on a firm bed, not just the
bell ends.
What part of the collection system pumps wastewater to a higher level? - ANSWER-
Sewage lift stations
Where does the building drain end? - ANSWER-2' outside the building wall or
foundation.
Why are manholes placed in a sanitary sewer system? - ANSWER-To allow
maintenance personnel and their equipment access to the collection system.
What are the three primary factors that affect the proper operation of a sewer main? -
ANSWER-Proper size, slope, and lack of obstructions.
What is the operational effect of oversizing a sewer main? - ANSWER-The wastewater
will have a tendency to leave solids behind.
What is the fall of a 3" building sewer? - ANSWER-Not less than 1/4" per foot.
What is the ideal flow rate of wastewater in a sewer main? - ANSWER-2 fps
