UNIVERSITY OF THE ORANGE FREE STATE

Department of Quantity Surveying and Construction Management

Faculty of Science

DEGREE IN QUANTITY SURVEYING/CONSTRUCTION MANAGEMENT/ ARCHITECTURE

ENGINEERING SCIENCE 312

Date : 19th May 1999

Examiner : Mr J.A.J. de Beer Time : 2 hours

Moderator : Mr B.J. Swart Marks : 50

F NOTE

(1)  All questions must be answered.

(2)  Please write clearly and legible.

(3)  No pencils may be used in answering any of the questions or in sketches.

(4)  Students may amplify their answers by means of sketches.

(5)  Questions may be answered in Afrikaans or English.

QUESTION 1

Suppose you are the City Engineer of one of the major cities in South Africa. At one of its regular meetings the City Council resolved that the local regulations relating to plumbing and drainage work be adapted to comply with modern standards and techniques.

You are instructed to make a thorough investigation of the plumbing and drainage Regulations relating to both South Africa and Great Britain.

The assignment also requires you to compare both sets of Regulations to determine the advantages and/or disadvantages of each Regulation concerned in both countries, indicate which of the Regulations can be adapted to suit local prevailing conditions and which Regulations of either of the countries will or should receive preference for inclusion into the local Regulations.

You are required to make the necessary recommendations to the City Council and to properly motivate each of your recommendations. (25)

QUESTION 2(a)

Make a complete sketch of an electric water heating installation, quote the names of all the components which forms part and parcel of the installation and indicate the relevant colours of the hot and cold water pipes and fittings. (10)

QUESTION 2(b)

Indicate the principals on which an electric water heating installation functions. ( 5)

QUESTION 2 (c)

What is understood by the term “balanced cold or hot water”? Give a detailed description of this and explain how it is attained. ( 5)

QUESTION 3

A double storey building comprises of two separate flats, one on each floor. Each flat contains three toilets, a sink, a wash hand basin and a bath.

Prepare a sketch of an elevation of the building with all the stack pipes indicated thereon, quote the name of each and every pipe forming such stacks and also state the three differences between a one-pipe and a two-pipe system.

In which type of building may a two-pipe system not be used. (10)

QUESTION 4

(a)  What is the maximum depth of the water in a trap?

(b)  What is the short title of the Act on National Building Regulations?

(c)  In the absence of a municipal sewerage system, quote the names of the two different methods you will use to dispose of the sewerage effluent?

(d)  What is the minimum slope of a sewer?

(e)  What is the maximum slope of a sewer?

(f)  What are the minimum requirements for an inspection chamber?

(g)  What are the minimum requirements for a manhole?

(h)  What is the minimum diameter of a sewer?

(i)  What is the minimum thickness of ground cover required over an underground sewer?

QUESTION 5

(a)  Quote the name of the unit that is used to measure the off-flow of a sewer.

(b)  Where three toilets each having a trap diameter of 100 mm and also two baths, two sinks and two showers each having a trap diameter of 40 mm are installed, what will the total off-flow in units be?

(c)  What is understood by the term “Velocity of the Sewer?”

(d)  Which factor determines the velocity of the sewer?

(e)  What influence will insufficient water supply have on the functioning of the sewer?

QUESTION 6

Describe fully the method of “In Situ-Seepage Test for Soil” that you will employ to determine whether the soil on a particular spot is suited for the installation of a French Drain. Also indicate the most advantageous for the installation of a French Drain.

QUESTION 7

(a)  Who will you consult to obtain the measurements of an erf?

(b)  Who will you consult to obtain the position, location and depth of a sewer connection?

(c)  What is meant by the term – “the fall of the ground is positive in relation to that of the site sewer?”

(d)  What steps will you take in the event of a sewer connection not having being installed by the Local Authority when you want to commence with the installation of the sewer?

(e)  Which factors influence the volume of sewer effluent from a site.

(f)  How will you accomplish a connection where the branch sewer joins the site sewer but the invert level of the branch sewer is higher than that of the site sewer? What type of connection is forbidden?

(g)  Where a stack enters the ground, what is the maximum distance permissible between an access to such sewer and the ground level?

(h)  Quote the four positions in a site sewer where it is compulsory to install a rodding eye.

QUESTION 8

(a)  What is the role of traps in a sewerage installation?

(b)  How many shapes of traps appear in a sewerage installation?

(c)  Quote the three different ways in which a water seal in a trap can be destroyed.

(d)  Give a brief description of one of the different ways in which a water seal in a trap can disappear.

(e)  Describe how a water seal in a trap can effectively be protected. Give a brief description of what happens in such a case.

QUESTIONS 9

a)  What is the short title of the Act on National Building Regulations?

b)  What is the minimum diameter of an underground sewer?

c)  What is the minimum slope of an underground sewer?

d)  What is the maximum slope of an underground sewer?

e)  What are the minimum requirements for an inspection chamber?

f)  What are the minimum requirements for a manhole?

g)  What is the minimum coverage required over an underground sewer?

h)  In the absence of a municipal sewerage system quote the names of two options that you will install? (10)

QUESTION 10

In the event of the top end of a sewer, due to the particular circumstances prevailing on the site, being laid on top of the natural ground surface and the sewer therefore requiring protection against heavy loads being superimposed on the sewer, describe how the sewer will have to be protected against possible damage? ( 5)

QUESTION 11

Quote the five cases where a French drain due to the five particular cases prevailing on the site, may not be installed on the site? ( 5)

QUESTION 12

Quote the main components which forms a complete sewerage system, name the functions of each component, including those components that are excluded and quote the owners of each component. (15)

QUESTION 13

a)  Quote the name of the unit which is used to measure the off-flow from fittings?

b)  Where four baths, four wash hand basins, two showers and two washing troughs are installed each having a trap diameter of 40 mm. What will the total off-flow in units be?

c)  In the event of six toilet pans, each having a trap diameter of 100 mm, two sinks and two showers, each having a trap diameter of 40 mm, being installed, what is the number of units that will be generated? ( 4)

QUESTIONS 14

a)  Who will you consult to obtain the measurements of an erf?

b)  Who will you consult to obtain the position and depth of a sewer connection?

c)  What is meant by the term – “the fall of the ground is positive in relation to that of the site sewer?”

d)  Where a stack enters the ground, what is the maximum distance between an access to such sewer stack and natural ground level?

e)  Name the four positions in a site sewer where it is compulsory to install a rodding eye.

f)  Under what circumstances is it permissible to discharge storm water into a sewer?

g)  There is a close relationship between the carrying capacity of a sewer and the speed at which the sewer flows. What is the name of the term used?

h)  What is understood by the term “Invert Level?” (11)

QUESTION 15

Make a complete list of all the differences in plumbing work and sewerage installations as it occurs between South Africa and Great Britain and indicated in the book edited by Mr Chadderton. Also indicate what your preferences are in relation to each individual requirement and also give your full motivation in regard to each of your preferences. (50)

QUESTION 16

Compile a list of all the components that occur in a two-pipe stack system. Also indicate the major differences between a two-pipe system and a single stack system. (12)

QUESTION 17

Make sketches, not necessarily according to scale, of the layout as well as the sections through, of a sewerage layout where a septic tank having two compartments and a French drain is to be used. Kindly also make a list of all the components. (25)

QUESTION 18

You are being requested to compile a complete drainage plan for a dwelling on a erf with a positive slope towards the street. Kindly make a complete sketch not necessarily to scale and also make a list of all the components which form the system. (20)

QUESTION 19

You have been requested by your client to advise him on the feasibility of installing a french drain on a given portion of land. Give a comprehensive report on how you will go about to prepare this report and also what steps you intend taking to substantiate your findings and also state what your findings should be. ( 6)

QUESTION 20

Quote the name of the units in which the off-flow into a sewer is expressed.

In a building there are 6 baths, 6 basins and 6 showers together with 6 toilets. What will the total number of such units that flow into the sewer, be? ( 4)

QUESTIONS 21(a)

Make a sketch of the longitudinal section through a gully where the water trap is being maintained by the discharge of the waste water from a wash hand basin. Also indicate the name of each of the components and all the particular measurements that are applicable. Please note that the one side of the gully is paved whereas the other side consists of normal ground. ( 7)

QUESTION 21(b)

Please indicate how you will go about to protect the water trap in a gully in the absence of a wash hand basin. ( 3)

QUESTION 22

Please indicate in full how you would go about to proof that the feature of Syphonic action in actual fact does exist. Also describe in full where this phenomenon occurs in the drainage field and what steps are taken to eliminate it. Make some sketches to amplify your answers and quote the names of the relevant components. (18)

QUESTION 23

Suppose you are a Consulting Civil Engineer. You have been appointed by an Architect to design the underground site drain on a private site. The frontage of the erf is 30 meters and the length thereof is 45 meters. The natural ground on the site has a slight negative slope of 1 meter over the entire length of the site but the depth of the sewer connection on the street side is sufficient to compensate for this negative slope in the ground. Describe fully step by step how you will go about to execute this assignment. The proposed building comprises a double storeyed block of flats containing four units. Make the necessary sketches to amplify your answer in full. (20)

QUESTION 24

List the seventeen requirements which must appear on a site plan.

QUESTION 25
Suppose you are a lecturer in Civil Engineering at this University.

You have been requested to give a lecture, which will last about an hour, to a group of first year students which have enrolled about three weeks ago for the first time for the degree of B.Sc. in Civil Engineering.

The lecture is entitled:

“A comprehensive study into all aspects relating to the components, installation, functions as well as the ownership of underground sewerage systems:

Give a comprehensive description of all the aspects relating to this subject which you will include in the lecture.

QUESTION 26

Suppose you are the chief fire officer for Bloemfontein. You are called upon to inspect and approve of the entire fire fighting installation of a building. The complex comprises of a three storey block of offices with ten offices per floor each office having a floor area of ten square meters, and also a warehouse with a floor area of five-hundred-and ten square meters. There is also an adjoining storeroom with a floor area of forty square meters and where alcohol is stored.

Give a full account of which items you will be inspecting and also which kind of fire extinguishers you will allow for which kind of fire and what kind of alternative fire extinguisher you will accept and what requirements you will lay down for every such alternative fire extinguishers.

Also quote ten different classifications for occupations of buildings. (60)

QUESTION 27

Make a complete drawing of a longitudinal civil engineering section of a site sewer, do all the necessary calculations that are applicable and indicate all the necessary information on the drawing. A sketch plan of the site sewer, together with all the relevant ground levels are indicated hereunder.