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T1140(E)(N22)T NOVEMBER EXAMINATION

NATIONAL CERTIFICATE

PLUMBING THEORY N2

(11022052)

22 November 2016 (X-Paper) 09:00–12:00

Calculators and drawing instruments may be used.

This question paper consists of 5 pages and 4 diagram sheets.

(11022052) -2- T1140(E)(N22)T


DEPARTMENT OF HIGHER EDUCATION AND TRAINING REPUBLIC OF SOUTH AFRICA

NATIONAL CERTIFICATE PLUMBING THEORY N2

TIME: 3 HOURS MARKS: 100

INSTRUCTIONS AND INFORMATION 1. 2. 3. 4. 5. 6. 7. 8.

Answer ALL the questions. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. ALL questions, except for QUESTION 3.5 which must be answered on DIAGRAM SHEET 2 (attached), must be done in the ANSWER BOOK. All the sketches and/or diagrams must be done in pencil, neat, reasonably large, in proportion and fully labelled. ALL the abbreviations and symbols MUST comply with the latest National Building Regulations and ALL relevant SABS codes. Rule off across the page on completion of EACH answer. Write neatly and legibly.

(11022052) -3- T1140(E)(N22)T


QUESTION 1: COLD-WATER SUPPLY 1.1 List the THREE stages of the hydrological (water) cycle. (3) 1.2 Name THREE common impurities found in untreated water. (3) 1.3 Describe what is meant by the term permanent hard water. (3) 1.4 Descibe why it is important that a zone valve should be in a closed position

during normal operations.

(2) 1.5 Draw a simple flow diagram to illustrate the stages of the public water

purification processes.

(7) 1.6 Name TWO valves or pipefittings used to prevent backflow of water. (2) [20] QUESTION 2: HOT-WATER SUPPLY 2.1 Briefly explain TWO functions of a vacuum breaker, each installed on the

cold-water inlet, and hot-water outlet side of a hot-water geyser.

(4) 2.2 Name the following symbolic signs used in drawings and sketches of water

installations. Write only the name next to the question number (2.2.1—2.2.4) in the ANSWER BOOK.

2.2.1 2.2.2

2.2.3 2.2.4 (4) 2.3 The drawing on DIAGRAM SHEET 1 (attached) shows a boiler and hot-water

cylinder. Write down the names of the SEVEN indicated components next to the corresponding question number (2.3.1–2.3.7) in the ANSWER BOOK.

(7)

2.4 High-pressure geyser installations are fitted with a pressure-control valve on

the cold-water inlet pipe. Describe the function of this valve.

(5)

[20]

T

(11022052) -4- T1140(E)(N22)T


QUESTION 3: DRAINAGE 3.1 Describe what is meant by the term sanitary group. (3) 3.2 Describe how the following stacks are connected to the underground drain in

the two-pipe system of arranging sanitary pipework.

3.2.1 Soil stack (2)

3.2.2 Waste stack (3) 3.3 Define what is meant by the term vent pipe. (2) 3.4 Make a neat, labelled, longitudinal sectional sketch of a typical septic tank. (10) 3.5 DIAGRAM SHEET 2 (attached) shows the plan detail of a house with an

outbuilding. Complete the underground drainage detail on the DIAGRAM SHEET to ensure an effective economical sewage-disposal system to the septic tank and french drain. Make use of the one-pipe drain (combined soil and waste water) system. Clearly indicate at least the following detail:

3.5.1 One ventilation pipe 3.5.2 One gulley 3.5.3 Sufficient access to facilitate cleaning 3.5.4 One inspection eye 3.5.5 Labels to all the relevant detail by means of standard

abbreviations.

NOTE: Write your examination number in the space provided and place

the completed diagram sheet in the ANSWER BOOK.

(15) [35] QUESTION 4: SHEET-METAL WORK AND FLASHING The sketch on DIAGRAM SHEET 3 shows a branch pipe connecting to a main at an angle of 45°. Apply the parallel-line method and develop the pattern of the branch pipe and the hole in the main pipe. Do not show any allowances for seams. Use scale 1 : 10.

[15]

(11022052) -5- T1140(E)(N22)T


QUESTION 5: CALCULATIONS The sketch on DIAGRAM SHEET 4 shows a water-supply tank with a diameter of 800 mm and a total depth of 750 mm. Calculate:

5.1 The maximum volume of water that the tank can hold (in litres). (5) 5.2 The pressure at tap 'A' if the tank is filled with water. (2) 5.3 The pressure at tap 'B' if the tank is filled with water. (3)

NB: Density of water = 1 000 kg/m3 and g = 10 m/s2

[10]

TOTAL: 100

(11022052) -1- T1140(E)(N22)T


DIAGRAM SHEET 1

T

Hot Water Storage Cylinder

Cold Water Storage Tank

2.3.1

2.3.2

2.3.6

2.3.4

2.3.3

Boiler

2.3.7

2.3.5

(11022052) -2- T1140(E)(N22)T


DIAGRAM SHEET 2: QUESTION 3.5

EXAMINATION NUMBER:

Outbuilding 6

3

1

2

5

2

4

5

Dwelling

1

3

BOUNDARY LINE

SEWER

SE

WE

R

CO

NN

EC

TIO

N

1 Water Closet

2 Sink

3 Wash Hand Basin

4 Bath

5 Shower

6 Wash Trough

(11022052) -3- T1140(E)(N22)T


DIAGRAM SHEET 3

300 m

m Ø

45º

Seam

300 mm Ø

800 mm

600 mm

Seam

(11022052) -4- T1140(E)(N22)T


DIAGRAM SHEET 4

5,5

m

10

0 m

m

75

0 m

m

800 mm Ø

Cold water supply

Stopcock

Fullway valve

Lid to prevent contamination

Water tank Overflow pipe

Base of tank

10

m

A

B



NOVEMBER EXAMINATION

PLUMBING THEORY N2

22 NOVEMBER 2016

This marking guideline consists of 8 pages.

MARKING GUIDELINE

MARKING GUIDELINE -2- T1140(E)(N22)T PLUMBING THEORY N2


QUESTION 1: COLD-WATER SUPPLY 1.1 Precipitation (rain, hail and snow)

Runoff and percolation (groundwater and underground water to sea)

Evaporation and transpiration (3 x 1)

(3)

1.2 Disease-producing organisms of enteric (intestinal) origin

Toxic substances most frequently derived from industrial wastes but can also come from the careless use of insecticides and other substances.

Biocides, even lead from lead pipes and -containers

Colouring, usually flushed from the nature of soil strata it passes through.

Turbidity generally carried in suspension by the erosion of clay deposits.

Organic matter that produces odours and bad tastes, such as the odour of hydrogen sulfide upon decomposition.

Carbon dioxide that enables water to take up calcium, magnesium and lead into solution.

Iron and manganese are taken into solution in the absence of dissolved oxygen.

Algae, which release characteristic odours and tastes.

Disinfecting chlorine, which may produce objectionable tastes unless chlorination is well managed.

(Any 3 x 1)

(3)

1.3 Permanent hardness is caused by the sulphates, chlorides and nitrates of

calcium and/or magnesium. These salts are taken into solution without the presence of carbon dioxide.

(3)

1.4 Being supplied from different service reservoirs (which are usually at

different elevations), these reticulation networks will be operating under different water pressures (static).

If the zone valve is open, the water from the higher reservoir will overflow out of the lower reservoir.

(Allocate TWO marks for any other reasonably correct exposition)

(2)



1.5

(7)

1.6 Swing type non-return (check) valve

Spring type non-return (check) valve

Vacuum breakers (Any TWO applicable valves or pipes fittings to be accepted as correct)

(2)

[20]

Source (Dam)

Screening

Coagulation

Mixing

Sedimentation

Filtration

Sterilisation

Storage (Control

Reservoir)

Service Reservoirs

Service Reservoirs

Service Reservoirs

Reticulation Network

Zone Valve

ONE mark EACH for any SEVEN

sequential

stages.



QUESTION 2: HOT-WATER SUPPLY 2.1 ON COLD-WATER SIDE

Break the siphon that could empty the hot-water cylinder to inlet level and burn out the element.

Prevents backflow of hot water to cold-water taps.

Prevents the contamination of fresh water supplies. ON HOT-WATER SIDE Prevents the collapse of hot-water cylinders. Facilitates draining of the geyser when required. Prevents back siphonage on hot-water lines.

(Any 2 x 2)

(4)

2.2 2.2.1 Vacuum breaker 2.2.2 Temperature and pressure safety valve 2.2.3 Pressure-control valve (combination of pressure-reducing valve

and pressure-relief valve)

2.2.4 Fullway valve (4 × 1) (4)

2.3 2.3.1 Cold-water service pipe/supply from meter 2.3.2 Cold-water feed pipe 2.3.3 Primary return pipe 2.3.4 Primary flow pipe 2.3.5 Expansion pipe/steam pipe 2.3.6 Secondary flow pipe 2.3.7 Tap-off points/terminal points

(7 × 1) (7) 2.4 The pressure-control valve reduces the incoming mains pressure to a preset

pressure rating and maintains and controls this pressure when the system is not in use.

(5)

[20] QUESTION 3: DRAINAGE 3.1 Sanitary group is a combination of sanitary fixtures that comprise not more

than one of each of a WC-pan, bath, shower, sink and either two wash-hand basins or one wash-hand basin and one bidet.

(3)

3.2 3.2.1 The soil stack is connected directly to the underground drain by

means of an open connection (two 45° bends OR one 90° long radius bend).

(2)

3.2.2 The waste stack discharges its contents into a gulley that is

connected to the underground drain via a gulley trap (closed connection).

(3)



3.3 Except in the case of a separate vent pipe, a vent pipe is that portion of the

stack above the last branch connection that is extended vertically to above the eaves and terminates in accordance with certain regulations.

(2)

3.4

(7)

SKETCH:

General correctness

Inlet T correct

Outlet T correct

Screen wall

Screen-wall opening½

Screen-wall gap for gas½ (Any THREE labels x ONE mark each)

(3)



3.5 (15) [35]

Outbuilding 6

3

1

2

5

2

4

5

Dwelling

1

3

BOUNDARY LINE

SEWER

SE

WE

R

CO

NN

EC

TIO

N

1 Water closet WC

2 Sink S

3 Wash hand basin WHB

4 Bath B

5 Shower SW

6 Wash trough WT

RE 1

RE 2

RE 3

RE 4

IE

G

110 Ø uPVC

U/G Drain Pipe

110 Ø

uP

VC

U/G

Dra

in P

ipe

Stubstack with 50 Ø vent as offshoot

Stubstack with 50 Ø vent as offshoot

Effective layout 3

Economical layout 3

Gulley 1

Cleaning provision 2

IE at sewer connection 1

RE at sewer connection 1

Abbr: Sanitary detail (4 x ½) 2

Abbr: Drainage detail (4 x ½) 2



QUESTION 4: SHEET-METAL WORK AND FLASHING [15]

0

4

2

3

4

5

6

1

5

3

2

1

0

Pattern of Branch Pipe

Curve of Interpenetration

Front View

Side View

0

1

2

3 4 5

6

0 1

2

3

4

5 6

0 6

1 5

2 4

3

0 1

2

3

4

5 6

0 6

1

2

1

2

3

4

5

5

4

3

3 3

Pattern of Hole

Scale 1 : 10

4

3

4

3

Pattern of Hole


Completed Side View


1 Completed Front View


Copyright reserved

QUESTION 5: CALCULATIONS 5.1

litres104

0001m104,0

65,04

8,0

1,075,04

8,0

H4

DVolume

3

2

2

2

(5)

5.2

kPa5,61

5,565,0100001

Hgp

(2)

5.3

kPa5,161

105,565,0100001

Hgp

(3)

[10]

TOTAL: 100

(11022052) -1- T1330(E)(A4)T

Copyright reserved

T1330(E)(A4)T APRIL EXAMINATION


PLUMBING THEORY N2

(11022052)

4 April 2016 (X-Paper) 09:00–12:00

Calculators and drawing instruments may be used.


(11022052) -2- T1330(E)(A4)T






Answer ALL the questions. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. ALL questions must be done in the ANSWER BOOK, except QUESTION 3.5 which must be answered on DIAGRAM SHEET 2 (attached). All the sketches and/or diagrams must be done in pencil, neat, reasonably large, in proportion and fully labelled. ALL the abbreviations and symbols MUST comply with the latest National Building Regulations and ALL relevant SABS codes. Rule off across the page on completion of EACH answer. Write neatly and legibly.

(11022052) -3- T1330(E)(A4)T


QUESTION 1: COLD-WATER SUPPLY 1.1 List the THREE stages of the hydrological (water) cycle. (3) 1.2 Name THREE common impurities found in untreated water. (3) 1.3 How can the term “permanent hard water” best be described? (3) 1.4 Zone valves should be in a closed position during normal operations.

Give TWO reasons to indicate why this is important.

(2)

1.5 Draw a simple flow diagram in sequentail order to illustrate the stages of the

public water purification processes.

(7) 1.6 Name TWO valves or pipe fittings that can be used to prevent the backflow of

water. (2)

[20] QUESTION 2: HOT-WATER SUPPLY 2.1 Name TWO functions of the vacuum breaker, of a hot water geyser when

installed on: 2.1.1 The cold-water inlet 2.1.2 The hot-water outlet

(4)

2.2 The following symbols are used on the drawings and sketches of water

installations. Name them according to the numbers 2.2.1 – 2.2.4 in your ANSWER BOOK.

2.2.1 2.2.2

2.2.3 2.2.4 (4)

T

(11022052) -4- T1330(E)(A4)T


2.3 The drawing on DIAGRAM SHEET 1 (attached) shows a boiler and hot-water

cylinder. Write down the names of the SEVEN components next to the corresponding question number (2.3.1–2.3.7) in your ANSWER BOOK.

(7)

2.4 High-pressure geyser installations are fitted with a pressure-control valve on

the cold-water inlet pipe. What is the function of this valve?

(5) [20]

QUESTION 3: DRAINAGE 3.1 Give a brief explanation of the term sanitary group. (3) 3.2 How are the following stacks connected to an underground drain in the 'two-

pipe system':

3.2.1 Soil stack (2) 3.2.2 Waste stack (3) 3.3 What is a vent pipe? List TWO facts. (2) 3.4 Make a neat, labelled longitudinal sectional sketch of a typical septic tank. (10) 3.5 DIAGRAM SHEET 2 (attached) shows the plan detail of a house with an

outbuilding. Complete the underground drainage detail to ensure an effective economical sewage disposal system to the septic tank and french drain. Make use of the one-pipe drain (combined soil and waste water) system. Clearly indicate the following in your detail:

3.5.1 One ventilation pipe 3.5.2 One gulley 3.5.3 Sufficient access to facilitate cleaning 3.5.4 One inspection eye 3.5.5 Lables to all the relevant detail by means of standard

abbreviations.

NOTE: Write your examination number in the space provided and

place the completed diagram sheet in the ANSWER BOOK.

(15) [35]

(11022052) -5- T1330(E)(A4)T

Copyright reserved

QUESTION 4: SHEET-METAL WORK AND FLASHING The sketch on DIAGRAM SHEET 3 (attached) shows a branch pipe connecting to a main pipe at an angle of 45°. Apply the parallel-line method and develop the pattern of the branch pipe and the hole in the main pipe. Do not show any allowances for seams. Use scale 1 : 10.

[15]

QUESTION 5: CALCULATIONS The sketch on DIAGRAM SHEET 4 (attached) shows a water-supply tank with a diameter of 800 mm and a total depth of 750 mm. Calculate:

5.1 The maximum volume of water that the tank can hold (in litres). (5) 5.2 The pressure at tap 'A' if the tank is filled with water (2) 5.3 The pressure at tap 'B' if the tank is filled with water (3) NB: Density of water = 1 000 kg/m3 and g = 10 m/s2 [10] TOTAL: 100

(11022052) -1- T1330(E)(A4)T


DIAGRAM SHEET 1

T

Hot Water Storage Cylinder

Cold Water Storage Tank

2.3.1

2.3.2

2.3.6

2.3.4

2.3.3

Boiler

2.3.7

2.3.5

(11022052) -2- T1330(E)(A4)T


DIAGRAM SHEET 2

EXAMINATION NUMBER:

Outbuilding 6

3

1

2

5

2

4

5

Dwelling

1

3

BOUNDARY LINE

SEWER

SE

WE

R

CO

NN

EC

TIO

N

1 Water Closet

2 Sink

3 Wash Hand Basin

4 Bath

5 Shower

6 Wash Trough

(11022052) -3- T1330(E)(A4)T


DIAGRAM SHEET 3

300 m

m Ø

45º

Seam

300 mm Ø

800 mm

600 mm

Seam

(11022052) -4- T1330(E)(A4)T

Copyright reserved

DIAGRAM SHEET 4

5,5

m

10

0 m

m

75

0 m

m

800 mm Ø

Cold water supply

Stopcock

Fullway valve

Lid to prevent contamination

Water tank Overflow pipe

Base of tank

10

m

A

B



APRIL EXAMINATION

PLUMBING THEORY N2

4 APRIL 2016


MARKING GUIDELINE

MARKING GUIDELINE -2- T1330(E)(A4)T PLUMBING THEORY N2


QUESTION 1: COLD-WATER SUPPLY 1.1 Precipitation (rain, hail and snow)

Runoff and percolation (groundwater and underground water to sea)

Evaporation and transpiration (3 x 1)

(3)

1.2 Disease-producing organisms of enteric (intestinal) origin

Toxic substances, most frequently derived from industrial wastes but can also come from the careless use of insecticides and other biocides, even lead from lead pipes and -containers.

Color, usually flushed from the nature of soil strata it passes through.

Turbidity generally carried in suspension by the erosion of clay deposits.

Organic matter that produce odors and tastes such as the odor of hydrogen sulfide upon decomposition.

Carbon dioxide that enables water to take up calcium, magnesium and lead into solution.

Iron and manganese are taken into solution in the absence of dissolved oxygen.

Algae, which release characteristic odors and tastes.

Disinfecting chlorine, which may produce objectionable tastes unless chlorination is well managed. (Any 3 x 1)

(3)

1.3 Permanent hardness is caused by the sulphates, chlorides and nitrates of

calcium and/or magnesium. These salts are taken into solution without the presence of carbon dioxide

(3)

1.4 Being supplied from different service reservoirs (which are usually at

different elevations) these reticulation networks will be operating under different water pressures (static).

If the zone valve is open, the water from the higher reservoir will overflow out of the lower reservoir.

(2)



1.5

(Any 7 x 1) (7) 1.6 Swing type non-return (check) valve

Spring type non-return (check) valve

Vacuum breakers (Any 2 x 1)

(2) [20]

Source (Dam)

Screening

Coagulation

Mixing

Sedimentation

Filtration

Sterilisation

Storage (Control

Reservoir)

Service Reservoirs

Service Reservoirs

Service Reservoirs

Reticulation Network

Zone Valve

ONE mark EACH for any

SEVEN sequential stages.



QUESTION 2: HOT-WATER SUPPLY 2.1

2.1.1 ON COLD-WATER SIDE Breaks the siphon that could empty the hot-water cylinder to inlet level

and burn out the element. Prevents backflow of hot water to cold-water taps. Prevents the contamination of fresh water supplies. 2.1.2 ON THE HOT-WATER SIDE Prevents the collapse of copper hot-water cylinders. Facilitates draining of the geyser when required. Prevents back siphonage on hot-water lines.

(Any 4 x 1)

(4)

2.2 2.2.1 Vacuum breaker 2.2.2 Temperature and pressure safety valve 2.2.3 Pressure-control valve (Combination pressure-reducing valve and

pressure-relief valve)

2.2.4 Fullway valve (4 x 1) (4) 2.3 2.3.1 Cold-water service pipe/supply from meter 2.3.2 Cold-water feed pipe 2.3.3 Primary return pipe 2.3.4 Primary flow pipe 2.3.5 Expansion pipe/steam pipe 2.3.6 Secondary flow pipe 2.3.7 Tap-off points/terminal points (7 x 1) (7) 2.4 Reduces the incoming mains pressure to a preset pressure rating and

maintains and controls this pressure when the system is not in use.

(5) [20]



QUESTION 3: DRAINAGE 3.1 It is a combination of sanitary fixtures that comprises not more than one of

each of a WC-pan, bath, shower, sink and either two wash-hand basins or

one wash-hand basin and one bidet .

(3)

3.2 3.2.1 The soil stack is connected directly to the underground drain by

means of an open connection (two 45° bends OR one 90° long radius bend) .

(2)

3.2.2 The waste stack discharges its contents into a gulley that is

connected to the underground drain via a gulley trap (closed connection).

(3)

3.3 Except in the case of a separate vent pipe, a vent pipe is that portion of the

stack above the last branch connection that is extended vertically to the elevation above the eaves and terminates in accordance with certain regulations.

(2)

3.4 General correctness

Inlet T correct

Outlet T correct

Screen Wall

Screen Wall opening

Screen Wall gap for gas

Sketch

(10)



3.5 (15)

[35]

Outbuilding 6

3

1

2

5

2

4

5

Dwelling

1

3

BOUNDARY LINE

SEWER

SE

WE

R

CO

NN

EC

TIO

N

1 Water Closet WC

2 Sink S

3 Wash Hand Basin WHB

4 Bath B

5 Shower SW

6 Wash Trough WT

RE 1

RE 2

RE 3

RE 4

IE

G

110 Ø uPVC

U/G Drain Pipe

110 Ø

uP

VC

U/G

Dra

in P

ipe

Stubstack with 50 Ø vent as off-shoot

Stubstack with 50 Ø vent as off-shoot

Effective Layout 3

Economical Layout 3

Gulley 1

Cleaning Provision 2

IE at Sewer Connection 1

RE at Sewer Connection 1

Abbr: Sanitary Detail (4x½) 2

Abbr: Drainage Detail (4x½) 2



QUESTION 4: SHEET-METAL WORK AND FLASHING [15]

0

4

2

3

4

5

6

1

5

3

2

1

0



Front View

Side View

0

1

2

3 4 5

6

0 1

2

3

4

5 6

0 6

1 5

2 4

3

0 1

2

3

4

5 6

0 6

1

2

1

2

3

4

5

5

4

3

3 3

Pattern of Hole

Scale 1 : 10

4

3

4

3

Pattern of Hole


Completed Side View


1 Completed Front View


Copyright reserved


litres104

0001m104,0

65,04

8,0

1,075,04

8,0

H4

DVolume

3

2

2

2

(5)

5.2

kPa5,61

5,565,0100001

Hgp

(2)

5.3

kPa5,161

105,565,0100001

Hgp

(3) [10]

TOTAL: 100


T1310(E)(N20)T



PLUMBING THEORY N2

(11022052)

20 November 2015 (X-Paper) 9:00–12:00

Calculators and drawing instruments may be used


(11022052) -2- T1310(E)(N20)T







(11022052) -3- T1310(E)(N20)T


QUESTION 1: COLD-WATER SUPPLY 1.1 Water intended for human consumption must be of acceptable quality

standards. Briefly describe any TWO general quality requirements for potable water.

(2) 1.2 Describe the chemical reaction during the softening process of the base-

exchange method.

(5) 1.3 Name THREE advantages why the water distributing mains of a city are

usually arranged according to a reticulation pattern. (3 × 1)

(3) 1.4 Describe the term water hammer. (2) 1.5 Water can be classified as temporary hard water and/or permanent hard

water. Briefly describe what temporary hardness of water means.

(3) 1.6 Water distribution networks are separated into pressure zones.

Briefly describe what is meant by the term pressure zone.

(3) 1.7 What is the purpose of a thermostatic valve in a hot-water installation? (2) [20] QUESTION 2: HOT-WATER SUPPLY 2.1 Name TWO disadvantages of an unbalanced hot-water installation as

compared to a balanced installation.

(2) 2.2 Make a neat, labelled, single-line diagrammatic sketch of a water heating

system with a 150 litre vertical geyser with a pressure rating of 400 kPa. Indicate all the required valves, pipes and fittings. Make use of symbols specified by the relevant SANS codes.

(8) 2.3 State ONE advantage and ONE disadvantage of a solar water-heating system

as compared to an electric, hot water-heating system.

(2) 2.4 Make a neat, labelled diagrammatic sketch of a boiler and cylinder system

with secondary return. The system is supplied with cold water from a cold water supply tank.

(8) [20]

(11022052) -4- T1310(E)(N20)T

Copyright reserved

QUESTION 3: DRAINAGE

3.1 What is meant by the term one-pipe system when referring to a sanitary pipe arrangement?

(3)

3.2 Fully describe the functioning of a septic tank with reference to the bacteriological processes occurring.

(7)

3.3 Any drainage installation must be adequately ventilated as prescribed by the National Building Regulations and other related national standards.

State THREE functions of ventilation pipes. (3 × 1)

(3)

3.4 Any drainage installation must be provided with adequate access to the installation, for the purposes of inspection, testing or internal cleaning.

Name FIVE instances where access to pipes should be provided. (5 × 1)

(5)

3.5 DIAGRAM SHEET 1 shows the plan detail of a house with an outbuilding. Complete the underground drainage detail to ensure an effective economical sewage disposal system to the septic tank and French drain. Make use of the one-pipe drain (combined soil and waste water) system.

Answer this question on the DIAGRAM SHEET and clearly indicate at least the following detail:

3.5.1 At least one ventilation pipe

3.5.2 One gulley

3.5.3 Sufficient access to facilitate cleaning

3.5.4 One inspection eye

3.5.5 Labels to all the relevant detail by means of standard abbreviations.

(17)

[35]

QUESTION 4: SHEET-METAL WORK AND FLASHING Apply the triangulation method and develop the pattern of the transition piece shown on DIAGRAM SHEET 2. Do not show any allowances for seams. Use scale 1 : 10.

[15]

QUESTION 5: CALCULATIONS

Determine all the pipe material, fittings and types of valves required to complete the hot and cold-water layout as shown on DIAGRAM SHEET 3. Tabulate the results neat and clearly.

[10]

TOTAL: 100

(11022052) -1- T1310(E)(N20)T


DIAGRAM SHEET 1

EXAMINATION NUMBER:

AFTER COMPLETION DETACH THIS DIAGRAM SHEET AND HAND IT IN WITH THE ANSWER BOOK

7

8

Dwelling

Outbuilding

4

1 Water Closet

2 Sink

3 Wash Hand Basin

4 Bath

5 Shower

6 Wash Trough

7 Septic Tank

8 French Drain

2

3 1

1

3

1

5 6

(11022052) -2- T1310(E)(N20)T


DIAGRAM SHEET 2

Seam

Seam

300 Ø

600

40

0

60

0

(11022052) -3- T1310(E)(N20)T

Copyright reserved

DIAGRAM SHEET 3

T

150 litre 600 kPa

22 Ø 22 Ø

15

Ø 15 Ø

15

Ø

22 Ø 15

Ø

15 Ø

15 Ø

22

Ø

22 Ø

NOTE: Use copper pipes with compression fittings

Roof space

First Floor

Ground Floor




PLUMBING THEORY N2

20 NOVEMBER 2015


MARKING GUIDELINE



QUESTION 1: COLD-WATER SUPPLY 1.1 The water should be:

Safe to drink

Attractive in appearance (sparkling)

Free of taste

Free of odour

Usable in a variety of household and industrial purposes.

Consumers may further demand that the water should be non-corrosive to metals, and contain enough fluoride to satisfy the physiological demands of

children for good dental health.√√

(Any 2 × 1)

(2) 1.2 The hard water has calcium and magnesium ions (positively charged)√ and

the zeolite has sodium ions (negatively charged).√

As the hard water filters through the zeolite, an exchange of ions takes place

between the sodium and the calcium and/or magnesium.√ Soluble sodium carbonate, sodium sulphate and/or chloride are formed.√

These soluble salts have no effect on the degree of hardness of the water.√

(5) 1.3 A more constant supply is maintained√.

Contamination of water supply is limited because dead legs, which creates

stagnant water, are prevented√.

Strategically placed valves allows smaller sections of the network to be

isolated during maintenance (less inconvenience to the consumer)√.

(3) 1.3 Water hammer refers to the incessant knocking and vibrating sound√√ in the

pipework.

(2) 1.5 Temporary hardness is caused by the bicarbonates√ of calcium and/or

magnesium√ held in solution by carbon dioxide√.

(3)

SODIUM ZEOLITE (in softener)

+ CALCIUM

SULPHATE (in water)

CALCIUM ZEOLITE (held in softener)

+ SODIUM

SULPHATE (in solution with

water but harmless)



1.6 A ‘pressure zone’ refers to the reticulation network/s√ that are supplied of a

specific service reservoir√√.

(3) 1.7 A thermostatic valve receives both cold and hot water (preferably at a

balanced pressure) and blends√ the water to a preset temperature√.

(2) [20] QUESTION 2: HOT-WATER SUPPLY 2.1 Poor temperature at mixer taps and shower outlets.√

The high pressure on the cold-water system increases the chances of

water hammer and pipe vibration.√

Noise levels are increased when cisterns and water tanks fill up through a

ball valve.

Splashing at water outlets are increased – especially in very high-pressure areas. (Any 2 × 1)

(2) 2.2

(8)

GVacuum Breaker

Vacuum Breaker

Type 3 Water Heat

100 litre 100 kPa

Temperature and Pressure Safety Valve

Isolating Valve

Hot

Wate

r F

eed t

o

Term

inal F

ittin

gs

Combination Pressure Control &

Expansion Relief Valve

Service Pipe from Mains Draining Tap

Cold

Wate

r F

eed t

o

Term

inal F

ittings

300 mm minimum

Anti-Syphonage Loop

T



2.3 ADVANTAGES:

Solar energy is used to heat the water – marked decrease in electricity

consumption – cost saving.√

A decrease in electricity consumption is more environment friendly.

DISADVANTAGES:

Not very effective in periods of no direct sunlight (cloudy periods)√

Costly installation.

Unsightly on roofs.

Added weight to the structure.

(2) 2.4

(8) [20]



QUESTION 3: DRAINAGE 3.1 The one-pipe system means a system of piping between the sanitary fixtures

and the underground drain in which both the soil water and waste water discharge down a common stack in which any trap venting or other venting

required might be via a common vent stack.√√√

(3) 3.2 The prime function of a septic tank is to condition the incoming raw sewage

so that the solids are largely separated from the water that then becomes less

offensive before it undergoes further treatment and disposal.√√

This results in three distinctive layers, viz:

Layer of sludge at the bottom,√

A relatively clear liquid in the middle and√

A scum layer floating at the top.√

The organinic matter is fermented and decomposed by the action of anaerobic bacteria, micro-organisms, maggots, worms and settles at the

bottom of the tank as sludge.√

Fats and grease that are not retained in the grease trap also collect in the

scum layer and usally remain there.√

(7) 3.3 A ventilation pipe (vent pipe) allows smell gasses and pathogenic gasses

to escape from the drainage installation at a safe height into the

atmosphere.√

A ventilation pipe prevents gasses from accumulating in the drains and

sanitary pipes.√

It also acts as an anti-syphonage provision.√

(3) 3.4 At a point within 1,5 m of the connection to the point of disposal.√

Within every 25 m on a straight run of drain.√

At the head of all drains.√

At the head of any branch drain longer than 6 m.√

Immediately before and after a drain runs under a building.√

Change of direction that exceeds 45° if a long radius bend is not used.

On a stubstack in a closed drainage system. (Any 5 × 1)

(5)



3.5

(17) [35]

QUESTION 4: SHEET-METAL WORK AND FLASHING

G

IE

RE 1

RH IE Single

Junction

LH IE Single

Junction

Stubstack with 50 Ø ventpipe as

offshoot

Stubstack (unvented)

11

0 Ø

uP

VC

UG

Dra

in P

ipe

ST

FD

Dwelling

Outbuilding

B

1 Water Closet

2 Sink

3 Wash Hand Basin

4 Bath

5 Shower

6 Wash Trough

7 Septic Tank

8 French Drain

S

WHB WC

WC

WHB

WC

SW WT

Stubstack (unvented)



[15]

x

A B

C D

0 1

2 3 4 5

6 5

4 3 2 1

1 0 2 3 4 5 6

A2

A3

A1

B5

A0

B4 B6 B3

True Lengths from B & C

True Lengths from A & D

True Length of Seam (x0)


Copyright reserved


MATERIAL LIST DESCRIPTION QUANTITY UNIT PRICE TOTAL

15 Ø Copper Pipe (Class 2) 56-60 m

22 Ø Copper Pipe (Class 2) 16-18 m

150 litre x 600 kPa Type 3 Geyser (horizontal)

01

22 mm x 600 kPa Combination Pressure Control & relief Valve (complete with TP-Valve,

01

22 mm Stopcock 01

22 mm Vacuum Breakers 02

22 mm Fullway Valves 01

15 mm Stopcocks 02

22 mm Equal Tee’s 05

22 x 22 x 15 Tee’s 03

22 x 15 x 22 Tee’s 01

22 x 15 x 15 Tee’s 02

[10]

TOTAL: 100


T1290(E)(A17)T

APRIL EXAMINATION


PLUMBING THEORY N2

(11022052)

17 April 2015 (Y-Paper) 13:00–16:00

Candidates will require drawing instruments.

Calculators may be used.


(11022052) -2- T1290(E)(A17)T






Answer ALL the questions. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. ALL the questions must be done in the ANSWER BOOK, except QUESTION 3.4 and QUESTION 4 which must be answered on DIAGRAM SHEET 1 (attached) and DIAGRAM SHEET 2 (attached) respectively. All the sketches and/or diagrams must be neat, reasonably large, in good proportion, fully labelled and done in pencil. ALL the abbreviations and symbols must comply with the latest National Building Regulations and ALL relevant SANS (SABS) codes. Rule off across the page on completion of EACH answer. Write neatly and legibly.

(11022052) -3- T1290(E)(A17)T


QUESTION 1: COLD-WATER SUPPLY 1.1 Describe the following terms: 1.1.1 Temporary hard water 1.1.2 Permanent hard water

(2 × 3)

(6) 1.2 What is the purpose of an air-release valve when installed on a long run of

water supply pipe?

(2) 1.3 The primary function of a fire hydrant is to provide easy access to an abundant

water supply, at a reasonably high pressure. It is however also used for other purposes. State THREE other functions of a fire hydrant.

(3) 1.4 Name THREE advantages of the gravity system of water supply to the

consumer as compared to the pumped system of water supply to supply tanks and water towers.

(3) 1.5 Describe the chemical reaction that occurs during the process of boiling

temporary hard water.

(6) [20] QUESTION 2: HOT-WATER SUPPLY 2.1 Make a neat, fully labelled diagrammatic sketch of an electrical hot-water

heating installation with a horizontal geyser with a pressure rating of 400 kPa. Clearly indicate all the required pipes and valves, including the antisyphon loop. Ignore the safety/drip tray. (7)

2.2 Old boilers and hot-water cylinders are usually clogged with salt deposits.

Describe how these salt deposits are formed giving at least THREE facts. (3)

2.3 Describe, with the aid of a simple sketch, how the expansion of the hot water is

relieved (during the heating process) in the combination hot-water geyser. (6) 2.4 Briefly describe the function of a pressure-relief valve when it is installed with a

pressure-control valve in a closed (unvented) hot-water installation.

(4) [20]

(11022052) -4- T1290(E)(A17)T


QUESTION 3: DRAINAGE 3.1 Describe the following drainage terms: 3.1.1 Drainage installation (3) 3.1.2 Rodding eye (2) 3.1.3 Manhole (2) 3.1.4 Septic tank (3) 3.2 Make a neat single-line longitudinal, sectional sketch of a typical conservancy

tank (vacuum tank) suitable for a domestic dwelling. Clearly indicate and label all the required detail, pipes, fittings and dimensions on the drawing.

(6) 3.3 The invert level of a drain is 625 mm at the head of the drain.

Calculate the invert depth at the first change of direction in the drain. The first section of pipe is 12, 75 m long and the drain has a gradient of 1 : 26.

(4) 3.4 Design an effective drain layout for the plan view of the domestic dwelling

shown on DIAGRAM SHEET 1 (attached). Label and describe all the pipes and fittings required to complete the installation. Write your EXAMINATION NUMBER in the space provided and place the completed DIAGRAM SHEET 1 in the ANSWER BOOK.

(15) [35] QUESTION 4: SHEET-METAL WORK AND FLASHING The figure on DIAGRAM SHEET 2 shows a pipe with a diameter of 200 mm, intersected at an angle of 45° by a branch pipe with a diameter of 300 mm. Draw the required elevation and develop the full pattern of the branch pipe as well as the pattern of the hole in the main pipe. Do not show any allowance for seams. Use scale 1 : 10. Write your EXAMINATION NUMBER in the space provided and place the completed DIAGRAM SHEET 2 in the ANSWER BOOK.

[15]

(11022052) -5- T1290(E)(A17)T


QUESTION 5: CALCULATIONS A water supply tank has a base area of 1,2 m by 1,2 m with a height of 900 mm. The overflow outlet is 200 mm from the top of the tank. Calculate:

5.1 The maximum volume of water that the tank can hold (3) 5.2 The mass of the tank if it is full of water

(The mass of the empty tank is 250 kg.)

(4) 5.3 The total area of material (in m2) required to manufacture the tank. Ignore any

allowance for seams or a lid.

(3) [10]

TOTAL: 100

(11022052) -6- T1290(E)(A17)T


DIAGRAM SHEET 1

EXAMINATION NUMBER:

1. Water closet

2. Wash hand basin

3. Bath

4. Sink

5. Shower

6. Washing machine

7. Wash trough

7

2

5

6 4

1 2

3

4

Domestic Dwelling

Outbuilding

Boundary

Bo

und

ary

Sewer Connection

Sewer

1

-1-

(11022052) -7- T1290(E)(A17)T


DIAGRAM SHEET 2

EXAMINATION NUMBER:

-2-

45º

100 mm

30

0Ø

300 Ø



APRIL EXAMINATION

PLUMBING THEORY N2

17 April 2015


MARKING GUIDELINE



QUESTION 1: COLD-WATER SUPPLY 1.1 1.1.1 Temporary hardness is caused by the bicarbonates of √

calcium and/or magnesium √

held in solution by carbon dioxide.√ (3 × 1)

(3)

1.1.2 Permanent hardness is caused by the sulphates, chlorides and

nitrates of √

calcium and/or magnesium. √

These salts are taken into solution without the presence of carbon dioxide. √ (3 × 1)

(3)

1.2 Automatically expel any air in the main √

without wasting water√ (2 × 1)

(2)

1.3 Provide water to emergency services to rinse/wash streets, etc. after

accidents. √

Provide access to fill municipal water tankers. √

Provide access to municipal workers to use water off a metered standpipe√

To be used as a temporary connection with approval by city engineers√. (Any 3 × 1)

(3)

1.4 This system is more economical as far as installation costs, operating

costs and maintenance costs are concerned. √

This system is more reliable and ensures a much more constant supply. The pump in a pump system must be interrupted to maintain or repair pumps. √

A more constant pressure is ensured. The only fluctuations of pressure at terminal fittings will occur at peak demands and changes of the water level in the service reservoir. √ (3 × 1)

(3)

1.5 Boiling the water also releases the carbon dioxide√ and the salts are

precipitated. √ This√ causes ‘furring’ (scaling) of hot-water systems. √

This causes blockages√ of hot-water systems and also leads to wastage√ of heat energy. √

(6)

[20]



QUESTION 2: HOT-WATER SUPPLY 2.1

(7) 2.2 If the system heats up (boils) temporary hard water, the carbon dioxide is

driven off and √

the bicarbonates of calcium and/or magnesium are thus not held in solution any more. √

These salts then precipitate in the system and √

settle to form the ‘scaling’. √ (Any 3 × 1)

(3)

100 litres x 400 kPa

horizontal geyser

20 Ø Hot- water outlet

to tap-off points

Vacuum breakers

300 mm above geyser

Temperature and pressure

safety valve

T

Full way valve/

Stop cock

Combination temperature control and

pressure-relief valve

Cold-water feed from main

supply ANTISYPHON LOOP

Drain cock



2.3

(6) 2.4 Reduce the incoming mains pressure√

to a pre-set pressure rating √

and maintain √

and control this pressure √

when the system is not in use√. (Any 4 × 1)

(4) [20]

QUESTION 3: DRAINAGE 3.1 3.1.1 A drainage installation of a site is vested in the owner of the

site√

It is intended for the reception, conveyance, storage or treatment of sewage. √

This includes sanitary fixtures, traps, discharge pipes, drains, ventilation pipes, septic tanks, sewage treatment works and mechanical appliances associated therewith. √ (3 × 1)

(3)

3.1.2 A rodding eye is a permanent access opening to the interior of a

drainage installation that √

permits full bore access to the interior of a drain for internal cleaning. √ (2 × 1)

(2)

Lid

Cold-water inlet

Overflow pipe

Expansion provision/Steam pipe

Insulation

Condensation cap

Hot-water cylinder

Cold-water feed to cylinder



3.1.3 A manhole is a chamber of depth exceeding 750 mm and of

such dimensions that √

enables a person to enter such a chamber to obtain access to a drain√ (2 × 1)

(2)

3.1.4 A septic tank is a chamber designed to receive sewage and√

to retain it for such a time and in such a manner as to √

secure adequate decomposition of the sewage. √

A septic tank is always installed with a French drain. √ (Any 3 × 1)

(3)

3.2 (6) 3.3

mm4,490

26

175,12

GradientcetanDisFall

√√

mm4,1151

4,490625

FallDepthInvertDepthInvert HEAD

√√

OR Fall = Distance of drain (m) gradient = 12,75 26 = 490,4 mm√√

(4)



3.4 (15)

[35]

1. Water closet WC

2. Wash hand basin WHB

3. Bath B

4. Sink S

5. Shower SW

6. Washing machine WM

7. Wash trough WT

7

2

5

6 4

1 2

3

4

Domestic Dwelling

Outbuilding

Boundary

Bo

und

ary

Sewer Connection

Sewer

1

G

RE 1

RE 2

IE

Stub stack with 50Ø offshoot as vent pipe (or with vent valve)

100 Ø uPVC UG Drain Pipe

10

0 Ø

uP

VC

UG

Dra

in P

ipe

100 Ø x 45º uPVC Plain Single Junction

100 Ø x 45º uPVC Plain Bend

Effective Layout 3√√√

Economical Layout 3√√√

One Gulley 1√

TWO Ventilation Provisions 2√√

TWO Rodding Eyes 2√√

IE at Sewer Connection 1√

THREE Abbr. (sanitary fitments) 1½√

THREE Abbr. (drainage detail) 1½√




QUESTION 4

1

0

2

3

4

5

6

5

4

3

2

1

0

0 0

0

0

6 6

6

1

1 1

2

2 2

3

3 3

4

4 4

5 5 5

5 5 1 1

1 5

6 4 4

4

2 2

2

3 3 3

0

1

1

2

2

3

3

3

3

4

4

5

5

6

Pattern of the hole -√√√√√=5 Curve of penetration-√√√√√=5 Pattern of branch pipe-√√√√√=5

=

√

PATTERN OF BRANCH PIPE

SCALE 1 : 10

CURVE OF INTERPENETRATION

[15]



QUESTION 5: CALCULATIONS 5.1 5.1.1 √√√

(3)

5.1.2

√√√√

(4)

5.1.3 √√√

(3) [10]

TOTAL: 100

3008,1

7,02,12,1

2,09,02,12,1

m

HBLVolume

kg33010

25008010

25010008,11000

250gVD

mmMASS WATERTANKTOTAL

2

SIDESBASETOTAL

m76,5

32,444,1

08,1444,1

9,02,142,12,1

AAAREA


T1300(E)(N12)T



PLUMBING THEORY N2

(11022052)

12 November 2014 (Y-Paper) 13:00–16:00

Candidates will require drawing instruments. Calculators may be used.


(11022052) -2- T1300(E)(N12)T






Answer ALL the questions. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. ALL the questions must be answered in the ANSWER BOOK, except QUESTION 3.5 which must be answered on DIAGRAM SHEET 1 (attached). ALL the sketches and/or diagrams must be neat, reasonably large, in good proportion, fully labelled and done in pencil. ALL the abbreviations and symbols MUST comply with the latest National Building Regulations and ALL relevant SANS-codes. Rule off across the page on completion of EACH answer. Write neatly and legibly.

(11022052) -3- T1300(E)(N12)T


QUESTION 1: COLD-WATER SUPPLY 1.1 Name ONE type of gas that can be used to sterilise water during the public

water purification process.

(1) 1.2 What effect does acidic soft water have on: 1.2.1 Copper pipes 1.2.2 Galvanized pipes

(2 × 2)

(4) 1.3 List FOUR common causes that could lead to vibrations and 'water hammer'

in the pipework. (2 x 2)

(4) 1.4 Water mains are usually arranged in a reticulation network from the service

reservoirs to the consumers. Make a neat diagrammatic sketch of a typical 'ring water reticulation' layout.

(5)

1.5 Can permanent hard water be softened by means of boiling? Motivate your

answer.

(2) 1.6 Thermostatic valves are sometimes installed in public places such as

hospitals, clinics and old-age homes. What is the purpose of installing these valves?

(1)

1.7 What is meant by the term pressure zone in the distribution and reticulation of

water to the consumer?

(3) [20]

QUESTION 2: HOT-WATER SUPPLY 2.1 List the working principles of the temperature and pressure safety valve when

it is activated by:

2.1.1 An abnormal increase in temperature in hot water 2.1.2 An abnormal increase in pressure in the hot water

(2 × 5)

(10) 2.2 Give ONE advantage and ONE disadvantage of a water solar heating system

when compared to an electric hot-water heating system.

(2) 2.3 When hot-and cold-water installation takes place what is meant when it is said

to have a balanced pressure?

(2) 2.4 Name any TWO functions of a vacuum breaker when it is installed in a hot-

water installation. (2 × 2)

(4)

(11022052) -4- T1300(E)(N12)T


2.5 Pressure control (reducing) valves are colour-coded to identify their various

nominal working pressures. Name the correct colour coding to identify the following pressure ratings:

2.5.1 400 kPa 2.5.2 600 kPa

(2 × 1)

(2) [20]

QUESTION 3: DRAINAGE 3.1 Name TWO factors that need to be considered when determining where to

place a conservancy or vacuum tank, intended for the disposal of sewage.

(2)

3.2 In the process of conveying potable drinking water state the minimum

distance at which supply pipes should be away from an underground drain when they:

3.2.1 Are laid horizontally next to each other 3.2.2 Cross each other

(2 × 1)

(2) 3.3 List FOUR facts that describe the one-pipe system with particular reference to

the arrangement of sanitary pipework on walls.

(4) 3.4 Name the TWO requirements recommended by the National Building

Regulations with regard to the minimum capacity (volume) of a septic tank for a single dwelling.

(4)

3.5 Design an effective drain layout for the plan view of the domestic dwelling

shown on DIAGRAM SHEET 1 (attached). Label and describe all the pipes and fittings required to complete the installation. Make use of the SABS symbols and abbreviations. NOTE: Write your EXAMINATION NUMBER in the space provided and place the completed DIAGRAM SHEET 1 in your ANSWER BOOK.

(15)

3.6 With the aid of a simple, labelled sketch and word description, show the

control mechanism of a submersible pump in a subsoil water sump.

(8) [35]

(11022052) -5- T1300(E)(N12)T


QUESTION 4: SHEET-METAL WORK AND FLASHING Apply the triangulation method of pattern development and develop the pattern of the transition piece shown on DIAGRAM SHEET 2 (attached). Do NOT show any allowance for seams. Use scale 1: 10.

[15]

QUESTION 5: CALCULATIONS 5.1 A tank with a base of 1 200 mm x 1 600 mm and height of 1 500 mm is used as a water storage tank. Calculate:

5.1.1 The maximum volume of water (in m3) that the tank can hold (3) 5.1.2 The mass of the water and the tank when the tank is full of water

(The tank has a mass of 210 kg when it is empty.)

(4)

5.1.3 The area of the material (in m2) required to manufacture the tank

(Do NOT make any allowances for seams or wire edges. NOTE: The tank is open at the top. Density of water = 1 000 kg/m3)

(3) [10]

TOTAL: 100

(11022052) -6- T1300(E)(N12)T


DIAGRAM SHEET 1

EXAMINATION NUMBER:

1. Water closet

2. Wash hand basin

3. Bath

4. Sink

5. Shower

6. Wash trough

2 5

6

4

1

2 3

4

Domestic dwelling

Outbuilding

Boundary

Bo

und

ary

Sewer Connection

Sewer

5

Bo

und

ary

-1-

(11022052) -7- T1300(E)(N12)T


DIAGRAM SHEET 2

Ø 200 mm

37

5 m

m

400 mm

150 mm

25

0 m

m

Seam

Seam

Front View

Plan View

-2-




PLUMBING THEORY N2

12 NOVEMBER 2014


MARKING GUIDELINE



QUESTION 1: COLD-WATER SUPPLY 1.1

Chlorine√ Calcium hypochlorite (bleach powder) √ Chlorine dioxide√ Ozone√ Sodium hypochlorite√ Ammonia (with chlorine) √

(Any 1x1)

(1)

1.2 1.2.1 Copper is relatively safe because minute amounts of dissolved

copper is not poisonous √and soft water usually leaves a green tinge on the tubing which is quite harmless. √

1.2.2 The corrosion of metals (galvanised iron) is accelerated if the water

passes through organic soils (peaty areas) √ and it can be neutralised by the addition of limestone or chalk. √

(2 × 2)

(4)

1.3 VIBRATIONS IN PIPEWORK WATER HAMMER (4)

Excessive water velocity. √ Loose washer plate assembly

in stopcocks. √ Faulty washer in tap, stopcock

or mixer. √ Inlet pipe undersized. √

Any x2

Undersized piping. √ Incorrect valve installation. √ Loose piping. √ Air is trapped in pipes. √

Any x2

1.4

ERVEN

ERVEN

ERVEN

Supply from distribution mains√ Isolating valve√ Fire hydrant√

Metered consumer pipe√ Water mains√

Water mains reticulated 2

Valves 1

Hydrants 1

Metered Connections 1



(5) 1.5 Yes. √ The carbonic gases can be driven off by boiling. √ (2) 1.6 To ensure a safe preset temperature of the water at the terminal fitting√ (1) 1.7 Service reservoirs are not always situated on the same elevation (height).

This means that a reservoir, which is situated on a higher level, will automatically lose its water to a reservoir on a lower level if their reticulation networks are interconnected. √

It then also stands to reason that these reticulation networks will be operating under different water pressures (static). Reticulation networks from a specific reservoir will be isolated from networks that are supplied with water from another reservoir. These clusters of networks are termed pressure zones. √

These interconnections must be supplied with an isolating valve that will be closed under normal circumstances. These valves are called zone valves and isolate pressure zones. √

(3) [20]

QUESTION 2: HOT-WATER SUPPLY 2.1 2.1.1 ACTIVATED BY EXCESSIVE TEMPERATURE (+95 ºC) [SABS

198:1992 (5,4)]

When the water temperature reaches 93-98 ºC, the very stable wax in the probe expands rapidly. √

The plug above the wax then exerts an upward force against the piston. √

The force overcomes the force in the spring and the piston with washer is lifted off the seat of the outlet. √

The water passage is then opened and the very hot water is moved out. √

The water in the system is cooled by the incoming cold water. √

When the water reaches a temperature of not lower than 75 ºC the wax contracts and the temperature-pressure (TP) safety valve closes. √

(NOTE: An increase in temperature also leads to an increase in the pressure of the water in the system.)

(5)

2.1.2 (1, 5 TIMES IT’S NOMINAL PRESSURE RATING) SABS 198:

1992

The outlet of the TP-safety valve is closed off by a washer that is spring-loaded. √

When the force of the water (due to the pressure) overcomes the force in the spring, √

the washer is lifted off its seat and √

the water passage is opened. √

The water will then escape to the outside thus decreasing the pressure in the system. √

(5)



2.2 ADVANTAGES DISADVANTAGES

(2)

Solar (sun) energy is used to heat the water, marked decrease in the electricity consumption; cheaper

A decrease in electricity consumption is more environmentally friendly

(Any 1 x 1) √

Not very effective in periods of no direct sunlight – (cloudy periods)

Costly installation

Unsightly on roofs

Added weight to roof structure (Any 1 x 1) √

2.3

Both the hot- and the cold-water pressure are controlled by either the same:

water supply tank or√

pressure control valve√

(2)

2.4 Prevents the collapse of copper hot-water cylinders√√

Facilitates draining of the geyser when required√√

Prevents back syphonage on hot-water lines √ √ (Any 2 x 2)

(4)

2.5 2.5.1 Red√ 2.5.2 Green√

(2 × 1)

(2) [20]

QUESTION 3: DRAINAGE 3.1 Any conservancy tank shall be so placed and so designed that:

It must not become a source of nuisance or danger to health is not likely √

to endanger the structure of any building or√

any services on the site. √ (Any 2x1)

(2)

3.2 3.2.1 When they are laid underground horizontally next to each other,

they shall be laid at least 500 mm apart, and√

3.2.2 When they cross each other, the line of the drain shall be laid at

least 100 mm below that of the pipe conveying such potable water√ (2 × 1)

(2)

3.3 The one-pipe system means a:

system of piping between sanitary fixtures and the underground drain in which √

both soil water and waste water √

discharges down a common stack and in which√

any trap venting or other venting required may be via a common vent stack. √

(4)

3.4 1,7 m3√√

The expected daily flow. (whichever is greatest) √√

(4)



3.5 S√√√√ S√ (15)

1. Water closet

WC

2. Wash hand basin

WHB

3. Bath B

4. Sink S

5. Shower SW

6. Wash trough

WT

2 5 6

4

1

2 3

4

Domestic dwelling

Outbuilding

Boundary

Bo

und

ary

Sewer Connection

Sewer

5

Bo

und

ary

100

Ø u

PV

C U

G D

rain

Pip

e

100 Ø x 45º uPVC Plain bend √√√

100 Ø x 45º PVC Plain single junction

Unvented stub stack √√

RE 2√

IE

RE 1

Stub stack with 50Ø offshoot as vent pipe (or with vent valve) √√√√



3.6√√√√

DIAGRAMMATIC LAYOUT OF SUMP PUMP CONTROL MECHANISM (3 marks for a suitable sketch + 2 x ½ for suitable lables)

(4)

Operation of switch: 1. The float rises with the water (sewage) until it is against the adjustable

stopper at maximum level. √

2. It eventually exerts enough pressure against the stopper and lifts the brass

rod which then switches the motor and pump on. √

3. The liquid is then pumped out of the accumulating sump; the level of the liquid

(and thus also the float) drops. √

4. The float drops onto the adjustable stopper at the minimum level. √ 5. The weight of the float and the rod pulls the switch down. The motor is then

switched off. √

6. The level of the liquid rises and the process is repeated. √

(4 marks for a suitable description)

(4) [35]

Stopper at maximum

level

Pump lever mechanism

Current level of liquid

Heavy float

Stopper at minimum level

Brass guides to stabilize brass rod

Brass rod



QUESTION 4: SHEET-METAL WORK AND FLASHING NOTE: Because the transition piece is symmetrical about the horizontal axis, only the true lengths of the top half OR the bottom halve need to be determined.

[15]

Seam

x

A B

C D

1

0

2 3 4 5

6

True length of seam

2 2

1

2

B 3 B 4

B 5

B 6

A 0 A 1

A 2

A 3

Neatness 2√√

Line work 3√√√

Base Lines 5√√√√√

Segments of circle 3√√√ Smooth arc 2√√




(3)

5.2

(4)

5.3

(3) [10]

TOTAL: 100

232,10

92,18,46,3

6,12,15,16,125,12,12

22

m

BaseSidesLongSidesShortmaterialofArea

kg

kgVolumeDensity

kofMasswaterofMassMassTotal

0903

2102880

21088,20001

210

tan

388,2

5,16,12,1

500160012001

m

mmm

mmmmmm

HeightWidthLengthwaterofVolume


T1260(E)(J22)T

AUGUST EXAMINATION


PLUMBING THEORY N2

(11022052)

22 July 2014 (Y-Paper) 13:00–16:00

Candidates need drawing instruments.

Calculators may be used.


(11022052) -2- T1260(E)(J22)T







(11022052) -3- T1260(E)(J22)T


QUESTION 1: COLD-WATER SUPPLY 1.1 Describe the object of filtration during public water purification. (4) 1.2 With the distribution of water to the consumer, the water flows to service

reservoirs before entering the reticulation networks. List THREE functions of a service reservoir.

(3)

1.3 Describe the chemical reaction that takes place during the base exchange

water softening process.

(6) 1.4 Water intended for human consumption must comply with a minimum of

acceptable quality standards. Briefly describe THREE of these general quality requirements for potable water.

(3)

1.5 Name the minimum required flow rates and the accompanying pressure

values for the following as stipulated by the National Building Regulations:

1.5.1 Fire hose reels

1.5.2 Fire hydrants

(2 x 2)

(4) [20]

QUESTION 2: HOT-WATER SUPPLY 2.1 Briefly explain the working principle of each of the vacuum breakers. (3) 2.2 The pressure of a hot-water installation can be decreased to a specific water

pressure rating by installing a pressure control valve. Describe how a typical pressure control valve works in order to decrease and control the pressure in a hot-water installation.

(6)

2.3 Make a neat single-line diagrammatic sketch of two electric vertical geysers

(type 3 water heaters) interconnected in a hot-water installation.

(8) 2.4 List THREE disadvantages of solar water heating panels. (3)

[20]

(11022052) -4- T1260(E)(J22)T


QUESTION 3: DRAINAGE 3.1 Describe the following drainage terms: 3.1.1 Inspection eye (3)

3.1.2 Preliminary treatment of sewage (at sewage treatment plants) (4)

3.1.3 Stub stack system (sanitary wall arrangement) (3) 3.2 Give THREE reasons why drainage work should be thoroughly tested and

approved by the local authority.

(3) 3.3 The invert level of a drain is 400 mm at the head of the drain. Calculate the

invert depth at the first change of direction in the drain. This first section of pipe is 9,5 m long, and has a gradient of 1 : 40.

(4)

3.4 The plan view on DIAGRAM SHEET 1 shows a domestic dwelling with an

outbuilding in a rural area. The sewage must be conveyed to the septic tank and French drain.

3.4.1 Use the diagram sheet and design in single lines, in accordance

with the relevant regulations, an underground drainage layout for the sewage disposal system.

(8)

3.4.2 Clearly indicate the following details: One gulley (1)

One ventilation pipe (1)

Adequate access to the drain (2)

Standard abbreviations for any THREE sanitary fitments (3)

Standard abbreviations for any THREE drainage details (3) [35]

NOTE: Write your examination number in the space provided and place the

completed DIAGRAM SHEET in the ANSWER BOOK.

QUESTION 4: SHEET METAL WORK AND FLASHING Apply the triangulation method and develop, in your ANSWER BOOK, only the full pattern of the transition piece shown on DIAGRAM SHEET 2. Do not show any allowance for seams. Use scale 1 : 10. HINT: Turn the page lengthwise.

[15]

(11022052) -5- T1260(E)(J22)T


QUESTION 5: CALCULATIONS The drawing on DIAGRAM SHEET 3 shows a domestic dwelling with a uPVC sanitary wall arrangement. List at least TEN pipe fittings that will be required to complete the sanitary installation.

[10]

TOTAL: 100

(11022052) -6- T1260(E)(J22)T


DIAGRAM SHEET 1

EXAMINATION NUMBER:

1

1

2

2

3

3

4

4

1. Bath

2. Water Closet

3. Wash Hand Basin

4. Sink

5. Septic Tank

6. French Drain

5

6

DWELLING

OUTBUILDING

-1-

(11022052) -7- T1260(E)(J22)T


DIAGRAM SHEET 2

EXAMINATION NUMBER:

50

0

PLAN VIEW

SIDE VIEW

300 Ø

-2-

(11022052) -8- T1260(E)(J22)T


DIAGRAM SHEET 3

EXAMINATION NUMBER:

50 Ø

WC

B

S WC

WHB

WHB

B

40 Ø

110 Ø

110 Ø

110 Ø

40 Ø

40 Ø

Scale 1 : 50

-3-



AUGUST EXAMINATION

PLUMBING THEORY N2

22 JULY 2014


MARKING GUIDELINE

MARKING GUIDELINE -2- T1260(E)(J22)T PLUMBING THEORY N2


QUESTION 1: COLD-WATER SUPPLY 1.1 To allow the untreated water to √

pass through layers of material √

while treated chemically to √

remove bacteria and microscopic suspended matter from the water √

(4)

1.2 Provides water to the consumer. √

Ensures an adequate reserve (usually a two- to three-day supply) of water in case of an interruption to the supply from the water treatment plant or control reservoirs. √

Provides the necessary pressure head to the water mains. √

Convenient place to regulate and control the water supply and quality thereof. √ (Any 2 x 1)

(2)

1.3 The hard water has calcium and magnesium ions that are positively

charged, and the zeolite has sodium ions. √

As the hard water filters through the zeolite, an exchange of ions takes place between the sodium and the calcium and/ or magnesium. √

Soluble sodium carbonate, sodium sulphate and/or sodium chloride are formed. √

These soluble salts have no adverse effects on the degree of hardness of the water. √

It does, however, leave a brackish taste in the water. √

The zeolite sodium base will eventually be completely changed to a calcium and/or magnesium base and will then not be able to soften the water. √

The zeolite must then be regenerated. √

(7)

1.4 Ordinary water should be safe to drink, √

attractive in appearance (sparkling), √

free from taste√

and odour and√

usable for a variety of household and√

industrial purposes. √ (Any 3 x 1)

(3)

1.5 1.5.1 Pressure:

Flow Rate: 300 kPa √ 0,5 litres/sec √

(2)

1.5.2 Pressure:

Flow Rate: 300 kPa √ 20 litres/sec √

(2) [20]



QUESTION 2: HOT-WATER SUPPLY 2.1 If a negative pressure (25 kPa below atmospheric) is created in the hot-

water system, √

the atmospheric pressure on the outside of the seal (washer) will overcome the force in the spring holding the washer in position. √

Air will enter the hot-water system and prevent the emptying of the geyser by syphonic action. √

(3)

2.2 The pressure control valve is separated into an inlet chamber and an outlet

chamber by a washer held in position by a spindle and a pressure spring. √

This separation (closed position) is maintained due to the pressure of the water on the outlet side. √

When the hot-water outlets are open the pressure in the outlet chamber is reduced. √

The force of the spring overcomes the force of the pressure in the outlet chamber and thus moves the valve off its seat to open the passage of water to the outlet chamber to the tap-off points. √

When the tap-off point is closed, the build of pressure on the diaphragm compresses the pressure spring and the washer seats onto opening to the outlet chamber. √

This again isolates the inlet chamber from the outlet chamber and the pressure control valve is in a closed position. √

(6)



2.3 (8) 2.4 Not very cost-effective during periods of no direct sunshine√

Costly installation√

Unsightly on roofs√

Added weight to be carried by roof structure. (Any 3 x 1)

(3) [20]

T T

1 4

2

3

5

6 7

OPERATING PRINCIPLES: BOTH GEYSERS FUNCTIONAL: Valves Open: 1, 2, 3, 4 and 5 Valves Closed: 6 and 7 ONLY GEYSER A FUNCTIONAL: Valves Open: 1, 2, 3 and 7 Valves Closed: 4, 5 and 6 ONLY GEYSER B FUNCTIONAL: Valves Open: 6, 3, 4 and 5 Valves Closed: 1, 2 and 7

A B

TWO Vertical Type 3 Geysers

2

Series Operation 2

Parallel Operation (By-passes)

2

Appropriate Symbols

4 x ½

2



QUESTION 3: DRAINAGE 3.1 3.1.1 An inspection eye is an access opening to the interior of any

pipe or pipe fitting in a drainage installation provided solely √

for the purpose of inspection and testing, and to which √

permanent access after completion of the drainage installation need not be provided. √

(3)

3.1.2 Because sewage contains materials such as rags, plastics,

pieces of wood, not to mention occasional cans and bottles, these items must be removed first. √

This is achieved by passing all incoming flows through a set of screens. These consist of a series of vertical bars set in the flow channel such that each bar is about 25 - 30 mm. √

Anything that will not pass through such a gap will be arrested on the bars and periodically raked off or deposited on to a conveyer belt immediately. √

This material is then compressed to squeeze out as much of the water as possible to reduce the volume before being discharged to a container for burial off the site. √

Following screening flows pass through a grit removal machine called a detritus, that is a shallow tank designed to slow the velocity of the flow down to precisely 0,3 m/s.

At this speed any gritty material settles on the floor of the tank from which it is constantly removed by a scraper mechanism, while the lighter organic material is kept in suspension.

If rags, grit, etc. are not removed from the flow at the beginning of the treatment works, this will cause blockages in the pipe work and severe abrasion in the pumps and other equipment used in the subsequent stages. (Any 4 x 1)

(4)

3.1.3 Stub stack refers to a common soil and waste stack √

not more than one storey high √

with a rodding eye of 100 mm at the top. √

(3)

3.2 Drainage work and sanitation in general are closely linked to public

hygiene and the health of humans. √

Because a great deal of the drainage system is underground, any defect or leakage will not be detected immediately and foundations could be damaged. √

The quality of materials and workmanship must ensure years of carefree and effective service. √

(3) 3.3

√√

mm2375,0

40

15,9

GradientcetanDisFall

√√

mm5,637

5,237400

FallDepthInvertDepthInvert HEAD

(4)



3.4 (18)

[35]

1

1

2

2

3

3

4

4

1. Bath

2. Water Closet

3. Wash Hand Basin

4. Sink

5. Septic Tank

6. French Drain

5

6

DWELLING

OUTBUILDING

G

RE 1

RE 2

IE

10

0 Ø

uP

VC

UG

Dra

in P

ipe




Unvented Stub stack



QUESTION 4: SHEET METAL WORK AND FLASHING [15]

600 Ø

300 Ø

50

0

e

a

b

c d

f

g 0

1

2

3

4

5

6

a b c d e f g

0 1 2 3 4 5 6

Vert

ical he

ight

= 5

00 m

m

PLAN VIEW

SIDE VIEW

Plan lengths of 0a, 1b, 2c, 3d, 4e, 5f, 6g

Plan lengths of 0b, 1a, 1c, 2b, 2d, 3c, 3e, 4d, 4f, 5e, 5g, 6f

TRUE lengths of 0a, 1b, 2c, 3d, 4e, 5f, 6g

TRUE lengths of 0b, 1a, 1c, 2b, 2d, 3c, 3e, 4d, 4f, 5e, 5g, 6f

Plan View 2

Front View 1

True Length of Diagonals

2

Plotting Points 2

Bottom Curve 2

Top Curve 2

Neatness 1

Linework 1

g g

f f

e e d d

c c b b a

6 6

5 5

4 4

3 3

2 2 1 1 0

Pattern of development




No Description Quantity Unit Price Amount

1 110 Ø uPVC Pipe 8 m

2 50 Ø uPVC Pipe 1,5 m

3 40 Ø uPVC Pipe 5 m

4 110 mm Pan Connector with Rubber Seal 2

5 110 mm x 95º IE Bends 2

6 110 mm x 95º Single Junctions 2

7 Basin Trap (40 mm x 1¼”) 2

8 Basin Waste Outlet Fitting (Chromium Plated) (1¼”)

2

9 Bath Trap (With Integral Overflow) (40 mm x 1½”) 2

10 Bath Waste Outlet Fitting With Overflow Fitting (1½”)

2

11 Double Bowl Sink Waste Assembly (40 mm x 1½”)

1

12 Double Bowl Sink Waste Outlets Fitting (1½”) Complete with Overflow Fitting and Flexible Overflow Pipe

1

13 Sink Trap (40 mm x 1½”) 1



16 50 mm x 95º Plain Single Junctions 2

17 50 mm x 40 mm Solvent Weld Reducer 4

18 100 mm x 50 mm x 95º Plain Single Junction 2

19 110 mm Vent Cowl 1

20 110 Ø Pipe Clips 8



23 500 ml Solvent Weld Cement / Glue 1

24 500 ml Lubricant 1

[10] TOTAL: 100

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