3. Sanitary Plumbing Single Stack System

Transcription

1 3. Sanitary Plumbing Single Stack System On completion of this section, students should be able to: Design, install and develop bills of quantities for the Single Stack Systems for domestic, commercial and industrial premises of over SIX (6) floor levels and interpret sanitary plumbing design for the systems. Assessment Criteria 3.1 Describe, design, install and develop bills of quantities for single stack sanitary plumbing systems for domestic, commercial and industrial premises to meet the requirements of the Building Code of Australia, Plumbing Code of Australia and AS/NZS Describe, design, install and develop bills of quantities for single stack modified sanitary plumbing systems for domestic, commercial and industrial premises to meet the requirements of the Building Code of Australia, Plumbing Code of Australia and AS/NZS Assessment Method may include Written assessment based on assessment criteria. Practical activities based on assessment criteria. Designs based on assessment criteria. Assignment based on assessment criteria Section 3-1

2 3.1 Describe, design, install and develop bills of quantities for single stack sanitary plumbing systems for domestic, commercial and industrial premises to meet the requirements of the Building Code of Australia, Plumbing Code of Australia and AS/NZS Refer Plumbing & Drainage Guide (BRANZ) If a multi-story building can be designed within the parameters of a single stack system, then this will usually be the simplest and most economic method of providing sanitary plumbing. A single stack system: a) is generally designed around stacks of DN 100 diameter, but there are variations to this; b) is based on the principle that there is sufficient air within the system for a number of fixtures to be connected to the stack without the need to vent individual fixture discharge pipes; c) the load effect of fixtures connected to the stack d) the maximum number of floor levels permitted to be connected to the stack are limited e) the class of the building (Residential or Commercial) f) where relief vents and cross-vents are installed and g) the number and type of fixtures permitted to be connected at any one floor level Principles of Operations Refer AS/NZS Clause The single stack systems are designed on the principles that the air within the discharge pipes from fixtures, the stack and the stack vent allows the permitted type and number of fixtures to be connected to the stack without the need for individual trap vents/air admittance valves or, in the case of ranges of fixtures, venting of the common discharge pipe. Section 3-2

3 Sizing of Stacks Residential Buildings Refer AS/NZS Clause 8.7 Stacks are sized by totalling the individual fixture unit ratings as given in Table 6.1 and considering the maximum number of floors through which the stack may pass (see Table 8.3), if the point at which the stack connects to the drain is more than 2.4 m below the lowest floor level, then that length of pipe must be counted as a floor level (refer AS/NZS Figure 8.3). Sizing Single Stack Systems for Domestic or Residential Buildings Using AS/NZS students are to complete the table below Size of stack DN Table 8.3 Single Stack System Domestic or Residential Buildings Maximum fixture unit loading Maximum number of consecutive floor levels The maximum number and type of fixtures that are permitted to be connected at any floor level for a residential building are: Refer AS/NZS Clause basins 2 baths 2 bidets 2 cloths-washing machines 2 dishwashing machines 2 kitchen sinks (double or single domestic with or without food waste disposal units) 2 laundry troughs 2 showers 2 water closet pans 2 floor waste gullies 2 bar sinks Section 3-3

4 STACK VENT (SEE CLAUSE 8.6) B Tr. (L) WC Shr S WC B Shr Bth. WC Shr B FW Tr. (L) S B WC Shr Bth. B FW Tr. (L) WC Shr WC B Shr Bth. WC Shr B FW Tr. (L) FW S WC OBLIQUE JUNCTION B Shr Bth. B FW Tr. (L) WC Shr S B Ground WC Shr Bth. FW OBLIQUE JUNCTION Fig. 3.1 Single stack residential building Section 3-4

5 Sizing Single Stack Systems for Commercial or Industrial buildings Using AS/NZS students are to complete the table below Size of stack DN 100 Table 8.4 Single Stack System Commercial or Industrial Buildings Maximum fixture unit loading Maximum number of consecutive floor levels The maximum number and types of fixtures that are permitted to be connected at any floor level for a commercial or industrial building are: Refer AS/NZS Clause basins 1 cleaner s sink 1 drinking fountain 1 sink 5 wall-hung urinals 5 water closet pans 2 showers 1 x 3 m slab type urinal 2 bar sinks Note: No additional or alternative fixtures shall be connected except tundishes receiving minor discharges. At any one floor level, the maximum discharge from all floor waste gullies shall not exceed five basins, one drinking fountain, one cleaner s sink and two showers (see Note 3 to Table 6.1). Within commercial and industrial buildings the following fixtures may be connected in a range of fixtures as listed below and shown in Fig. 8.2: i) 5 basins; ii) iii) 5 wall-hung urinals; and 5 water closet pans. The conditions for the connection method will be covered later in this learning outcome. If your design does not fall within the conditions mentioned, then you would need to consider a Fully Vented Modified System. Section 3-5

6 Fig. 3.2 Single stack commercial or industrial building Section 3-6

7 Connection of Fixture Discharge Pipes In domestic or residential buildings, fixtures shall be connected to the stack individually or through floor waste gullies. In commercial or industrial buildings, fixtures may be connected to the stack individually, through floor waste gullies or in a range of the same type of fixtures. Unequal Oblique Stack Junction Refer AS/NZS As well as the above methods of connections, two waste fixture discharge pipes, including discharge pipes from floor waste gullies may be connected at the same level within 1 m of the stack, by means of an oblique junction if: a) the angle between the two fixture discharge pipes shall be not greater than 45. b) the outlet of the junction is one size larger than the largest fixture pipe except in the case of a floor waste gully that does not receive the discharge from a fixture; and. c) the section of pipe downstream of the 45 junction is included as part of the permitted maximum length of the fixture discharge pipe. STACK 1 m max. FIXTURE DISCHARGE PIPE 45 JUNCTION ONE PIPE SIZE LARGER THAN LARGEST FIXTURE DISCHARGE PIPE FIXTURE DISCHARGE PIPE 45 max. Fig. 3.3 Unequal oblique stack junction Section 3-7

8 Length of Fixture Discharge Pipes Length and gradients of unvented fixture discharge pipes Using AS/NZS students are to complete the table below Fixture type Waste fixture WC pan DN 100 WC pan DN 80 Urinal DN 50 to 80 Max. length (m) Permitted grade % Note: If the length of fixture discharge pipes exceeds that as outlined above and within Appendix D, then a Trap Vent or Air Admittance Valve must be fitted. As stated at the start of this learning outcome, a single stack system is designed on the principle that the air within the discharge pipes, the stack and stack vent allows the type and number of fixtures to be connected without the need for extra ventilation. Extra consideration has to be given to the fixture discharge pipes apart from size, length and grade; such as the number of bends. Section 3-8

9 Bends in fixture discharge pipes Refer AS/NZS Basins and Bidets Shall have not more than two bends in the horizontal plane and two bends in the vertical plane. Other Fixtures Shall have not more than two bends in the horizontal plane and three bends in the vertical plane. Note: Bends 45 or less are not considered as a change of direction or grade. If a design needed more than the allowed bends as stated above, the discharge pipe would need venting either via a trap vent or air admittance valve. Developed length of discharge pipe must not exceed 2.5 m Basin or bidet Stack or graded pipe DN 40 min. trap 1 st horizontal bend 1 st vertical bend Total drop of discharge pipe must not exceed 1.5 m 2 nd horizontal bend for basins and bidets the max. bends allowed are: two in the horizontal plane two in the vertical plane 2 nd vertical bend Refer Plumbing and Drainage Guide (BRANZ) Fig. 3.4 Connection of basins and bidets to a branch pipe or stack Section 3-9

10 Refer Plumbing and Drainage Guide (BRANZ) Fig. 3.5 Connection of fixtures other than basins and bidets to a branch pipe or stack Trap Vents and Air Admittance Valves on over distance discharge pipes. If the fixture discharge pipe is over distance, a vent or air admittance valve is required. This must be connected in accordance with the requirements set out in AS/NZS The size of the vent is dependant on the size of the fixture trap, using AS/NZS complete the table below Using AS/NZS students are to complete the table below TABLE 7.3 MINIMUM SIZE OF TRAP VENTS Size of fixture trap Size of trap vent DN DN >50 > Section 3-10

11 Show on the diagrams below the permitted points of connection for the trap vent and the maximum and minimum distance from the trap that the vent should be located No connections permitted within this distance 75 mm P-trap or S-trap 600 mm for basins/bidets 1.5 m for other fixtures A No connections permitted within this distance 300 mm min. 1.5 m max. 75 mm no connections permitted within this distance Connect vent/aav within this length B Connect vent/aav within either Section A or B FIG. 3.6 Connection of vents/aav to graded discharge pipes Using AS/NZS students are to complete the table below TABLE 6.6 MINIMUM DETERMINED AIRFLOW CAPACITY OF AIR ADMITTANCE VALVE WHEN USED AS A TRAP, GROUP VENT OR BRANCH DRAIN VENT Fixture unit loading of discharge pipe Minimum airflow capacity of AAV, L/s Section 3-11

12 Installation of Trap Vents. Trap vents and air admittance valves are installed in one of the following four ways. Draw the approved installation methods. Refer AS/NZS TRAP VENT OR AAV 100 mm min. TRAP VENT OR AAV FIXTURE TRAP 100 mm min. GRADE 1.25% min. (a) (b) TRAP VENT GRADE 1.25% min TRAP VENT OR AAV VENT TO RISE ABOVE RIM OF FIXTURE 100 mm min. ALTERATIVE USE AAV 100 mm min. GRADE 1.25% min. (c) (d) Fig. 3.7 vent installation. Venting of Stack Refer AS/NZS The stack shall continue upwards to the vent cowl undiminished in size. Stacks that extend not more than three floor levels with a maximum loading of 30 fixture units may have the vent reduced to DN 50. Section 3-12

13 Three waste fixtures only basins, showers or kitchen sinks may be connected to this top DN 50 vertical section. Refer AS/NZS Connection of ranges of fixtures This allows groups of fixtures of the same type, to be connected through a common branch pipe without the need for extra ventilation. Basins Refer AS/NZS The maximum number of basins shall be five The fixture discharge pipe shall be: a) of size DN 40; b) not longer than 1 m; c) installed with not more than one bend; and d) graded within the range of 2.5 to 5%. The common discharge pipe shall be: a) not smaller than DN 50; b) not longer than 4.5 m; c) installed without a bend; and d) graded within the range of 2.5 to 5%. The distance between the centre-line of adjacent traps and between the near face of the stack and the centre-line of the nearest trap shall not exceed 2 m. Section 3-13

14 2m max. between basin traps 2m max. from stack to first trap max. of five basins in a range common discharge pipe 4.5m max. with no bends; min. diameter DN 50 grade 2.5 to 5.00% Refer Plumbing and Drainage Guide (BRANZ) Fig. 3.8 Connection of a range of basins Section 3-14

15 Water Closet Pans Refer AS/NZS The maximum number of WC S shall be five The fixture discharge pipe shall be: a) not longer than 1.5 for S-trap pans and 2 m for P-trap pans; b) installed with a maximum of two bends; and c) graded within the range of 1.65 to 5%. The common discharge pipe shall be: a) not smaller than DN 100; b) not longer than 10 m; c) installed with not more than two bends; and d) graded within the range of 1.65 to 5%. The distance between the centre-line of adjacent traps and between the near face of the stack and the centre-line of the nearest trap shall not exceed 6 m. max. of five WC pans Fixture discharge pipe 2m max. for P traps stack 6m max. 6m max. combined discharge pipe max. of two 45 bends gradient 1.65 to 5.0% min. DN 100 max. length 10m Refer Plumbing and Drainage Guide (BRANZ) Fig. 3.9 Connection of a range of WC s p-trap Section 3-15

16 max. of five WC pans 1.5m max. dropper fixture discharge pipe: gradient 1.65 to 5.0% Max. of two bends 10 m max. combined discharge pipe max. of two 45 bends gradient 1.65 to 5.0% min. pipe size DN 100 max. length 10m Refer Plumbing and Drainage Guide (BRANZ) Fig Connection of a range of WC s s-trap Wall-hung Urinals Refer AS/NZS The maximum number of wall-hung urinals shall be five The fixture discharge pipe shall be: a) of size DN 50; b) not longer than 1 m; c) installed with not more than one bend; and d) graded within the range of 2.5 to 5%. The common discharge pipe shall be: e) not smaller than DN 65; f) not longer than 10 m; g) installed with not more than two bends; and h) graded within the range of 2.5 to 5%. Section 3-16

17 The distance between the centre-line of adjacent traps and between the near face of the stack and the centre-line of the nearest trap shall not exceed 2.5 m. max. of five wall-hung urinals 1m max. fixture discharge pipe min. grade 2.5 to 5.0% max. length 1m max. one bend min. size DN 50 combined discharge pipe min. size DN 65 max. length 10m max. of two bends gradient 2.5 to 5.0% Refer Plumbing and Drainage Guide (BRANZ) Note: Fig Connection of a range of wall-hung urinals If waterless urinals are used they must have two fixtures connected to the discharge pipe upstream of the urinal. Offsets in Single Stack Systems Refer AS/NZS An offset may be a steep offset, made up of angles of more than 45 to the horizontal. A graded offset, made up of an angle of less than 45 to the horizontal, with a minimum grade of 2.5% for DN 80 waste stacks and 1.65% for DN 100 or larger stacks. DN 100 stacks may be offset between the base of the stack and the highest connection as long as; the height of the stack must not exceed 10 floor levels; if laundry troughs are connected above the upper offset bend, the maximum fixture unit loading for the stack is not to exceed 50. Section 3-17

18 Using AS/NZS students are to complete the table below Maximum height in consecutive floor levels above the upper offset bend TABLE 8.9 OFFSET REQUIREMENTS Minimum distance between upper offset bend and connection of fixture discharge pipe Mm Minimum distance between lower offset bend and connection of fixture discharge pipe mm Maximum fixture unit loading STACK DN 100 min. 4th 3rd Min. DISTANCE (SEE TABLE 8.9) 45 2nd 600 mm min. 1st Ground TO SEWER Fig Typical steep connection Section 3-18

19 Steep offset below the lowest connection Refer AS/NZS Where a steep offset is below the lowest connection; the height of the stack must not exceed 3 floor levels; there is a maximum number of 30 fixture units permitted through the offset; laundry troughs shall not be connected. Lowest grades pipe 100 mm min. (see Clause 8.9.4) 45 To sewer Fig Steep offset below lowest connection Note: In an area where foaming is likely to occur, the minimum distance permitted at or near the offset may need to be increased. Section 3-19

20 Graded Offset Refer AS/NZS A DN 100 stack may be offset between the base of the stack and the highest connection as long as; only one graded offset is permitted; with a maximum of 10 consecutive floor levels; with a minimum of 2 m between centre-lines of vertical sections; The upper vertical section must be installed in accordance with Clause 7.6.2; and the graded lower vertical section in accordance with Table 7.8 Using AS/NZS students are to complete the table below TABLE 7.8 MINIMUM GRADE OF OFFSET Size of graded section Min. gradient DN % < Section 3-20

21 Stack vent (see Clause 8.6) 2 m min. or Air Admittance Valve as per AS/NZS Clause 6.9 WC only with DN 40 trap vent (600 min.) 900 min min. 450 min. 600 min. 900 min. Fig Graded offset Section 3-21

22 3.2 Describe, design, install and develop bills of quantities for single stack modified sanitary plumbing systems for domestic, commercial and industrial premises to meet the requirements of the Building Code of Australia, Plumbing Code of Australia and AS/NZS The single stack modified system permits stacks to receive a higher discharge loading or to be extended to serve a greater number of floor levels by introducing a relief vent and cross-vents. The cross-vents are installed between the stack and relief vent or the installation of pressure attenuators. The introduction of a relief vent and cross-vents into the system, allows for any excess pressure variations to be alleviated. The connection of the fixture and discharge pipes is the same as that covered for the single stack system; the only difference is the addition of a relief vent and cross-vents or the use of pressure attenuators. Using AS/NZS students are to complete the table below Size of stack DN TABLE 8.5 SINGLE STACK MODIFIED SYSTEM DOMESTIC OR RESIDENTIAL BUILDINGS Maximum fixture unit loading Maximum number of consecutive floor levels Size of relief vent and crossvent DN Location of cross-vents Alternate floors Each floor Alternate floors Each floor TABLE 8.6 SINGLE STACK MODIFIED SYSTEM OTHER THAN RESIDENTIAL TYPE BUILDINGS Maximum Size of stack DN fixture unit loading Location of cross-vents 100 Maximum number of consecutive floor levels Size of relief vent and crossvent DN Each floor Each floor Each floor Section 3-22

23 Fig 3.15 Single stack modified residential building Section 3-23

24 Fig Single stack modified commercial or industrial building Section 3-24

25 Waste Stacks Waste stacks may be used to pick up waste fixtures only; Using AS/NZS students are to complete the table below Size of stack DN TABLE 8.1 SIZE OF WASTE STACK Maximum fixture unit loading TABLE 8.7 WASTE STACKS LOADING PERMITTED THROUGH GRADED OFFSET Size of graded section of offset DN Maximum fixture unit loading permitted through the offset A DN 65 waste stack may receive the discharge from kitchen sinks and laundry troughs provided; the stack does not exceed two floor levels measured between its base and the highest floor level to which fixtures are connected; only two kitchen sinks or one kitchen sink and one laundry trough are separately connected at each floor level. Section 3-25

26 Acceptable Variations AS/NZS 3500 Clause 8.8 lists acceptable variations to the requirements for single stack system such as: a) A DN 80 stack up to three floors in height for domestic or residential buildings; b) A DN 80 stack up to two floors with the top section graded; c) A DN 100 stack up to three floors with the top section graded, receiving up to 30 fixture units; d) A DN 100 stack of one floor with the top section graded, receiving 90 fixture units; Students are encouraged to read these variation and the others listed to gain an understanding of the special conditions for their installation. Section 3-26

27 CPCPSN4011A Section 3 Student Name: Due date: Answer the following questions in the space provided Quote references. 1. Name the parts of the stack shown below as numbered. 1. STACK VENT 6. RELIEF VENT 2. FIXTURE TRAP 3. STACK 7. CROSS VENT 5. FLOOR WASTE GULLY 4. SINGLE STACK SYSTEM 8. SINGLE STACK MODIFIED SYSTEM 1) 2) 3) 4) 5) 6) 7) 8) Section 3-27

28 2. What is the principle a single stack system operates on? 3. What is the difference in design between a single stack and single stack modified systems? 4. What is meant by the term, Range of Fixtures? 5. In what type of building (classification) is a range of fixtures allowed to be installed, Section 3-28

29 6. A single stack sanitary plumbing system is possibly the most common type of stack design used in low rise domestic buildings. a) Explain THREE (3) benefits of this system. i) ii) iii) b) Explain TWO (2) disadvantages of the Single Stack system. i) ii) Section 3-29

30 Instructions: Complete the design below to comply with the requirements of AS/NZS Draw directly onto this sheet. Using the correct colour code. 2. Provide all pipe sizes. 3. Show the number of fixture units per floor and include a total. 4. Include any venting requirements and indicate where you would locate any Air Admittance Valve. Section 3-30