The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
How To Design And Install Plumbing
Federal authority in Recommended Minimum Requirements permits this type of ventilation, and their test proved it to be sufficient. Many states have used it for years and apparently have experienced no great or continuous amount of trouble with it. It does have a place in the ventilation of small fixture groups, or it may be used to advantage on the circuit-vent installation provided a fixture is wasted into it which has none but clear water discharge, such as a wash basin or drinking fountain. The scouring effect of the fixture wastes tends to increase the efficiency of the installation. It is entirely impractical, however, to waste a sink or similar fixture into the vent line because of the variety of fecal waste it discharges.
Sizing the Wet Vent. The wet vent size is determined in the same manner as is that of the individual vent. The unit system is the basis of its size. For example, suppose a wet vent is to be employed to ventilate a small fixture group consisting of a closet, lavatory, and bathtub. The unit values of these fixtures are: water closet, 6; lavatory, 1; and bathtub, 2. The sum of these values is 9 units. By referring to the table which lists the number of units permissible, page 178, only eight units may be ventilated by pipe of l1/2-inch diameter. Hence a 2-inch pipe must be used to ventilate this installation.
Wet Vent Installations. Fig. 171 illustrates a wet vent which may be used in connection with a small bathroom group of fixtures consisting of a closet, lavatory, and bathtub. In this instance the lavatory is installed on the increased diameter vent pipe which serves both the water closet and bathtub.
Other fixtures may be wet vented in the same manner, especially those of the floor variety, such as shower baths, urinals, slop sinks, and floor drains. It is not permissible, however, to ventilate wallhung fixtures by this method.
Fig. 172 shows how a lavatory or drinking fountain may be wasted into a circuit-vent installation. The circuit vent usually is of large diameter and does not become fouled readily. The lavatory serves as a wash for the vent line and unquestionably adds to its efficiency.
Looped Vent. The looped vent is a method of ventilation used on fixtures which are located in the room away from partitions that might be utilized to conceal the waste and vent. These installations are common in barber shops, beauty salons, and hospital surgical rooms.
