With the ordinary iron sink, having the bell attached to the strainer, what should be done after the kitchen sink has been properly trapped below?

The bell of the sink strainer should be broken off, otherwise the sink will be double trapped and will not run off freely.

How should the trap which serves the drainage of the cellar bottom be protected in order to avoid any danger caused by evaporation?

The line on which such trap is placed should enter the main drain on the house side of the main trap, which is always sealed. Without the main trap there is no other protection than its own seal. It, however, should be supplied with a trap screw to be used during the dry season. Unless the trap screw with rubber gasket is made use of, it should be seen to that water is occasionally poured into the trap to renew any loss that may have occurred.

Name advantages and disadvantages of the main trap.

The advantage claimed for it is that it safe-guards the house against the entrance of sewer gas through flaws or cracks in pipes and joints, also in the case of repairs when a fixture trap is disconnected temporarily. It prevents the pernicious effects of sewer gas on lead and iron pipes. It also acts as a protection to the cellar drainage trap, and to conductor pipes. The disadvantages claimed in its use are that it prevents the venting of the sewer through the main stack, that it acts as an impediment to the flow of sewage, and is likely to become fouled and to freeze up.

What style of trap should be used in hotel and restaurant kitchens?

The grease trap should be used in such places.

Describe some grease trap.

The Tucker Grease Trap is perhaps the most efficient. It is of the drum trap form, its entire body being surrounded by a passage which is connected with the cold water supply. The constant change of water keeps this water jacket always cool, and, as the waste enters the trap, the effect of the surrounding cold surface is to separate the grease from the liquid, allowing it to rise to the top, where it may be taken out through the cover. A partition through the middle of the trap prevents the grease from being carried out through the waste as it rises.

Plumbing For Residence.

What trouble may arise from double trapping?

The space between the two trap seals may become air bound and thus cause a slow passage of the waste, under which condition the stoppage of the waste is much more likely to take place.

Why should traps be counter-vented?

To prevent syphonage principally, to ventilate the plumbing system, and to relieve back pressure.

From which side of the trap should the counter-vent be taken?

From the sewer side of the trap.

What would be the result if the counter-vent were taken from the house side of the trap?

Syphonage could not be prevented, and the vent would become a by-pass for sewer gas.

Does experience show that counter-venting lengthens or shortens the life of the plumbing system?

Counter-venting lengthens it materially.