5 VENTS AND VENTING.pdf

Vents & Venting System Vents & Venting System VENTILATION Portion of the drainage pipe installation intended to maintain a balanced atmospheric pressure inside the system Vent Pipe- a pipe or opening used for ensuring the circulation of air in a plumbing system and for relieving the negative pressur...

Vents & Venting System Vents & Venting System VENTILATION Portion of the drainage pipe installation intended to maintain a balanced atmospheric pressure inside the system Vent Pipe- a pipe or opening used for ensuring the circulation of air in a plumbing system and for relieving the negative pressure exerted on trap seals. Vents & Venting System VENTS Main Types: Main Soil & Waste Vent the ‘backbone’ of the entire sanitary system Connected to the Main Soil & Waste Stack The portion where waste does not travel through Continues to the roof; the portion penetrating the roof is called the Vent Stack Through Roof (VSTR) Vents & Venting System Main Vent the principal artery of the venting system to which vent branches are connected. a.k.a. ‘Collecting Vent Line’ serves as support to the Main Soil & Waste Vent Vents & Venting System Individual Vent or Back Vent a pipe installed to vent a fixture trap, that connects with the vent system above the fixture served or terminates in the open air. Vents & Venting System Other Types: Unit, Common, or Dual Vent an arrangement of venting so installed that one vent pipe serve two (2) traps. Vents & Venting System Relief Vent a vertical vent line that provides additional circulation of air between the drainage and vent systems or to act as an auxiliary vent on a specially designed system such as a “yoke vent” connection between the soil and vent stacks. Vents & Venting System Yoke or By-pass Vent a pipe connecting upward from a soil or waste stack below the floor and below horizontal connection to an adjacent vent stack at a point above the floor and higher than the highest spill level of fixtures for preventing pressure changes in the stacks. Vents & Venting System Circuit Vent a group vent pipe which starts in front of the extreme (highest) fixture connection on a horizontal branch and connects to the vent stack. a.k.a. ‘Loop Vent’ Serves a battery of fixtures Vents & Venting System Looped Vent a vertical vent connection on a horizontal soil or waste pipe branch at a point downstream of the last fixture connection and turning to a horizontal line above the highest overflow level of the highest fixture connected there Used in spaces without partitions Vents & Venting System Wet Vent that portion of a vent pipe through which wastewater also flows through. Vents & Venting System Local Vent a pipe or shaft to convey foul air from a plumbing fixture or a room to the outer air. Dry Vent a vent that does not carry liquid or water-borne wastes. Vents & Venting System Stack Vent the extension of a soil or waste stack above the highest horizontal drain connected to the stack. Vent Stack the vertical vent pipe installed primarily for providing circulation of air to and from any part of the soil, waste of the drainage system. The uppermost end above the roof has traditionally been referred to as Vent Stack Through Roof (VSTR). Vents & Venting System REQUIREMENTS: Vents REQUIRED Each trap shall be protected against siphonage and back-pressure through venting. Vents NOT REQUIRED on a primary settling tank interceptor which discharges through a horizontal indirect waste pipe into a secondary interceptor. The secondary interceptor shall be properly trapped and vented. Traps serving sinks in an island bar counter. Such sink shall discharge by means of an approved indirect waste pipe into a floor sink or other approved type receptor. Vents & Venting System SIZE OF VENTS: The sizes of vent piping shall be determined from its length and the total number of fixture units connected thereto. The diameter of an individual vent shall not be less than 32 mm (1-1/4”) nor less in size than one-half (1/2) the diameter of the drain to which it is connected. Installation of Vents GRADES & CONNECTIONS All horizontal or branch vents shall be free from drops or sags & shall be graded and connected to drip back by gravity to the drainage pipe it serves. Each vent shall rise vertically 152 mm above the highest level rim of the fixtures served before offsetting horizontally. All vent pipes shall extend undiminished in size above the roof or shall be reconnected to the soil or waste stack vent at a point below the roof. The “vent stack through roof” (VSTR) shall be increased one (1) pipe size above the connection between the stack vent and the horizontal vent. Two (2) fixtures having same level inlet openings, may be served by a common vertical vent pipe connected to an approved double branch fitting. Installation of Vents VENT TERMINATION VSTR shall terminate vertically not less than 150 mm above the roof nor less than 300 mm from any vertical surface nearby. Each vent opening shall terminate: Not less than 3.00 m from any openable window; Not less than 0.90 m above any openable window; Not less than 0.90 m away from any lot line, alley and street boundary lines. Vertical vent pipes shall extend 3.00 m distant from any part of the roof that is used for human activities and shall extend not less than 2.10 m above such roof. Installation of Vents VENT STACK & RELIEF VENTS Each soil or waste stack extending ten (10) or more storeys above the building drain shall be served by a parallel vent stack which shall extend undiminished in size from its upper terminal at the roof and connect to the soil or waste stack at ground level and at every fifth floor levels with a “yoke vent” at a point below the horizontal soil or waste branch connection to the stack and at the nearby vent stack above the same floor to provide a relief vent. The size of yoke vent shall be not less in diameter than either the soil stack or the vent stack, whichever is smaller. The yoke vent connection at the vent stack shall be placed 1.0 m above the floor level and, by means of a wye branch at the soil stack, shall be placed below the fixture branch serving that floor. Vents & Venting System Trap Seal Loss - Direct effect of the Minus & Plus Pressure inside the system due to inadequate ventilation of traps - Attributed to the following conditions: Siphonage- direct and momentum Vents & Venting System Back Pressure Capillary Attraction Evaporation- caused by extreme temperatures, idleness Wind Effects- strong winds blow the trap seal Retardation of flow - Due to the effect of atmospheric pressure and/or gravity Deterioration of the Materials - Due to the formation of acids INDIRECT WASTE PIPING, WET-VENTED SYSTEMS & SPECIAL WASTES Indirect Waste Pipe – is a pipe that does not connect directly with the drainage system but conveys liquid wastes by discharging into a plumbing fixture, interceptor or receptacle directly connected to the drainage system. House Drain Appliances GREASE TRAPS: For establishments like restaurants, cafes, lunch counters, cafeterias, bars and clubs, hotel, hospital, sanitarium, factory or school kitchens. A grease trap is not required for individual dwelling units. No grease trap shall be installed for a facility that has an approved rate of flow of more than 3.4 liters per second (54.26 gpm) nor less than 1.3 L/s (20.74 gpm). Each grease trap shall have an approved water seal of not less than 51 mm in depth or the diameter of its outlet, whichever is greater. No food waste disposal unit shall discharge into a grease interceptor or grease trap. House Drain Appliances GREASE TRAPS: Used for fixtures where grease may be introduced into the drainage or sewer system in quantities that can effect line stoppage or hinder sewage treatment or private sewage disposal. 2 Main Types Earth Cooled Grease Trap Mechanical Grease Trap House Drain Appliances Operating Principles (separation of grease from water): grease suspended in waste floats to the surface Earth cooled Grease Trap Mechanical Grease Trap Traps & Interceptors Grease Trap Capacity TOTAL # OF FIXTURES CONNECTED REQUIRED RATE OF FLOW GREASE RETENTION CAPACITY 1 76 L/ min. 18 Kg 2 95 L/ min. 23 Kg 3 132 L/ min. 32 Kg 4 189 L/ min. 45 Kg House Drain Appliances HOUSE TRAPS: Placed in the house drain immediately inside the foundation wall of the building DRAIN TILES: Used to prevent groundwater from seeping through the basement walls & foundation Hollow tiles are placed around the perimeter of the foundation where water is collected; drain tiles are connected to the house drain or sump pit House Drain Appliances Garage Traps: a.k.a. garage catch basin Operating Principles: trap is filled with water & located at the lowest point of the garage so it can collect all wastes. House Drain Appliances Back Flow Valves: Used in house drain to prevent the unlikely occurrence of back flows Similar to check valves House Drain Appliances Sewage Ejectors: Pumps the wastes up form the sump pit to the sewers (which are usually higher than basement levels) Private Sewage Disposal Systems DISPOSAL PHASE- the final stage of the plumbing process; where used water and water-carried wastes are brought to various disposal outlets Definition: SEPTIC TANKS A watertight covered receptacle designed and constructed to receive the discharge of sewage from a building sewer, separate solids from the liquid, digest organic matter and store digested solids through a period of detention, and allow the clarified liquids to discharge for final disposal SLUDGE- solid organic matter that are denser than water and settle at the bottom of the septic tank SCUM- lighter organic material that rise to the surface of the water EFFLUENT- liquid content of sewage Private Sewage Disposal Systems Bacteria in septic tank to encourage decomposition: Aerobic bacteria- relies on oxygen to survive Anaerobic bacteria- can survive in places without oxygen Private Sewage Disposal Systems Minimum dimensionsL= 1500mm W=900mm D=1200mm Private Sewage Disposal Systems SINGLE CHAMBER SEPTIC TANK: Private Sewage Disposal Systems DESIGN CRITERIA: PLANS: should show all dimensions, reinforcing, structural calculations, and such other pertinent data as needed. QUALITY OF DESIGN: shall be such as to produce a clarified effluent of acceptable standards and shall provide adequate space for sludge and scum accumulations. MATERIALS: constructed of durable materials, not subject to excessive corrosion or decay, shall be watertight. Material: cement (most common) or pre-fabricated cast iron Private Sewage Disposal Systems COMPARTMENTS: have a minimum of 2 compartments: First compartment: not less than 2/3 capacity of the total capacity of tank; not less than 2 cum liquid capacity; shall be at least 0.9 m width and 1.5 m long; Liquid depth not less than 0.6 m nor more than 1.8 m. Secondary compartment: maximum capacity of 1/3 total capacity of tank; minimum of 1 cum liquid capacity In septic tanks having over 6 cum capacity, the secondary compartment should be not less than 1.5 m in length. maintain a slope of 1:10 at the bottom of the digestion chamber to collect the sludge and make it easily accessible from the manhole MANHOLES: with at least two (2) manholes, 508 mm in min dimension; one over inlet, other over outlet. Wherever first compartment exceeds 3.7 m in length, an additional manhole required over the baffle wall. Private Sewage Disposal Systems SIZES OF PIPE INLET & OUTLET & THEIR VERTICAL LEGS: Inlet and Outlet pipes – diameter size not less than the sewer pipe Vertical legs of inlet and outlet pipes – diameter size not less than the sewer pipe nor less than 104.6 mm. LENGTH AND LOCATION OF INLET & OUTLET: Shall extend 101.6 mm above and at least 304.8 mm below the water surface Invert of the inlet pipe shall be at a level not less than 50.8 mm above the invert of the outlet pipe. VENT DIAMETER: equal to the cross sectional area of the house sewer. Private Sewage Disposal Systems AIR SPACE: Side walls shall extend 228.6 mm above liquid depth. Cover of septic tank shall be at least 50.8 mm above the back vent openings. PARTITION (between compartments): An inverted fitting equivalent in size to the tank inlet, but in no case less than 104.6 mm in diameter, shall be installed in the inlet compartment side of the baffle with the bottom of the fitting placed midway in the depth of the liquid. Wooden baffles are prohibited. STRUCTURE: Shall be capable of supporting an earth load of not less than 14.4 kPa Private Sewage Disposal Systems CAPACITY: The capacity of septic tanks is determined by the number of bedrooms or apartment units in dwelling occupancies; by the estimated waste/sewage design flow rate for various building occupancies; or by the number of fixture units of all plumbing fixtures; whichever is greater. The capacity of any one septic tank and its drainage system shall also be limited by the soil structure classification in its drainage field. LOCATION: Should not be located underneath the house At least 15 meters from the water distribution system