ADVANCED BUILDING MEASUREMENTS

MEASUREMENT OF PLUMBING WORKS

Order of measurements

1. Connection to water authoritys main and all work up to boundary of site, including

reinstatement of public highway and provision of stop valve near the site boundary.

2. Underground service and rising main from site boundary up to cold water storage

tank, including any stop valves, holes through walls, ceiling and floors, lagging of

pipes, and the like.

3. Branches to rising main, such as supply to sink, including any associated works.

4. Cold water storage tank or cistern and associated work such as bearers, overflow,

cover and insulating lining.

5. Down service with branches, including any stop valves, holes through walls, ceiling

and floors and lagging of pipes.

6. Sanitary appliances such as sinks, wash basins, baths and water closets supply and

fixing, including supporting brackets, taps and the like.

7. Discharge pipes (waste, soil and vent pipes) and associated work.

8. Any other work connected with the plumbing installation, such as painting pipes and

testing the installation.

Drawing of plumbing installations -

The architects drawing normally gives little information on the layout of the water service

pipes in the building. The information supplied is frequently limited to the point of entry of

the rising main in to the building, the position of the cold water storage tank or cistern and the

various sanitary appliances. In these circumstances the quantity surveyor must decide on a

suitable layout of pipes and plot them on the various drawings, with the consultation of the

plumbing engineer. It is good practice to draw the various pipes in different colours, such as

the rising main in red and down service in blue.

Connection to water main -

The tapping and insertion of a ferrule to the water authoritys main and the provision of the

communication pipe from the main to the boundary of the site with a stop valve provided at

this point, including opening up and reinstatement of the highway and all watching and

lighting usually covered by a Provisional Sum (SMM A53.1.1 2.0.0).

Pipe Work -

Classified under appropriate headings, such as cold water system (S10 of Common

Arrangement) measured over all fittings and branches in meters stating the type,

nominal size, method of jointing and type, spacing and method of fixing supports

distinguish between straight and curved pipes (SMM Y10.1.1.1.0 and Y10.M3). Pipes are

deemed to include joints in their running lengths (SMM Y10.C3). The provision of

everything necessary for jointing is deemed to be included (SMM Y10.C.1). The type of

background to which the pipe supports fixed is classified in the categories listed in SMM

General Rules 8.3.

Details of the kind and quality of materials used in the pipes, gauge and other particulars

listed in SMM Y10.S1-6, and likely to be included in preamble clauses.

Made bends, special joints and connections, and fittings such as Y-junctions, reducers,

elbows, tees, and crosses are enumerated as items extra over the pipes in which they occur

(SMM Y10.2.1-4).

Pipe fittings 65 mm diameters are classified according to the number of ends, while those

of larger diameter are described.

Valves and cocks are classified as pipe work ancillaries and are enumerated, stating the type,

nominal size, method of jointing, type, number and method of supports and type of pipe to

which connected (SMM Y11.8.1.1.0).

Water storage tanks or Cisterns

Water storage tanks or cisterns are enumerated giving appropriate particulars (SMM

Y21.1.1.0.0). Timber supports to tanks are measured in meters with a dimensioned overall

cross-section description (SMM G20.13.0.1.0). Insulation to tanks or cisterns is enumerated,

giving the overall size of he tank, or insulations contained in casings can be measured in m2

(SMM Y50.1.4.1-2.0). Any pipe work located in the roof space should be insulated and this

insulation is measured in meters giving the type of insulation and nominal size of the pipe

(SMM Y50.1.1.1.0).

Holes for pipes

Cutting holes through the structure for pipes and making good structure are enumerated,

stating the nature and thickness of the structure and the shape of the hole, and classifying the

pipes to size in accordance with SMM P31.20.2.1 3.2 & 4. Ex: pipes 55 mm nominal size,

55 110 mm and > 110 mm.

Sanitary Appliances

Sanitary appliances include low level WC suits, WC pans and cisterns, urinals and cisterns,

sinks, wash basins, bidets, baths, showers and vanity units (Common Arrangement N13).

These appliances are enumerated giving details of the type, size, pattern and capacity, and

method of fixing (SMM N13.4.1.1.6). The supply of appliances is frequently covered by

prime cost sum, including relevant particulars and provision for main contractors profit

(SMM A52.1.1.1.0). Another alternative is to give supply and fix items with full details

(SMM General Rules 6.1).

Builders work in connection with plumbing installations

Builders work in connection with a plumbing installation is identified under an appropriate

heading (SMM P31.M2). Unless identified in SMM work sections P30 and P31, all other

items of builders work are given in accordance with the appropriate work sections (SMM

P31.M1).

Example Refer drawing in page no 8.

ADVANCED BUILDING MEASUREMENTS

MEASUREMENT OF MECHANICAL WORKS

General Background

The measurement of mechanical services installations requires a detailed knowledge of

technology. The drawings from which the quantity surveyor must work are those that are

prepared by the consulting services engineer. Consulting engineers are normally required to

prepare drawings and specifications sufficient to obtain tenders. These drawings are

schematic only, because trade practice is for the contractor to prepare all necessary working

drawings and to include in his tender for a complete working installation. The exact route of

pipe work and duct work is often left to the craft operatives doing the work. Therefore, the

quantity surveyor must put himself in the position of the operative and include in the bill of

quantities all items necessary for the complete installation.

Measurement Procedure

The first task is full study and understanding the drawings and specifications provided. A

study of these documents will lead to queries. These queries must be first submitted to the

consulting services engineer and clarified.

Approach to Measurement

Having acquired adequate information and full understanding of the scheme, taking off can

begin. Firstly, the drawings should be coloured up using a suitable colour code to illustrate

the various services to be measured. The drawings are mainly in the form of floor plans and it

is often helpful to draw a sketch of complicated sections of the work to be taken off in

isometric projection to illustrate the full extent of the work involved.

The process of measurement is relatively straightforward, comprising enumerated items of

plant at the source, a connecting network of pipe work or ducting measured linearly, with

enumerated fittings taken as extra over pipes and ducting, enumerated ancillaries, and finally

enumerated items for the emission plant and equipment. Special supports and sleeves for

pipes and ducting generate further enumerated items.

Work in plant rooms is identified separately because of the restricted working conditions

(SMM Y10/20/30.M2). Everything necessary for jointing is deemed to be included (SMM

Y10/20/30.C1) and full requirement of materials shall be given as prescribed in SMM

Y10/20/30.S1-6. Thermal insulation to pipelines and ducting is measured in meters giving the

nominal size of the pipeline or ducting, while insulation to equipment is enumerated giving

the overall size or measured in m2 (SMM Y50.1.1, 3 & 4.1.0).

Pipe fittings 65 mm diameters are grouped together irrespective of type, stating the number

of ends. With larger fittings the type is stated (SMM Y10.2.3 4.2 6.1 2). Examples of

pipe work ancillaries are draw-off taps, stop valves, control valves, non-return valves, drain

cocks, stop cocks, air cocks, mixing valves, steam traps, strainers, gauges and thermometers

and automatic controls.

Other Measurement Aspects

Work Sections

The rules for the measurement of mechanical services given in Work Group Y are billed

under separate work sections. Those work sections are;

R Disposal system includes sewage pumping and refuses chutes.

S Piped supply system includes cold water, hot water, steam, fire hose reels, dry risers, wet

risers and sprinklers.

T Mechanical Heating / Cooling / Refrigeration Systems includes gas / oil fired boilers,

coal fired boilers, heat pumps, solar collectors, low temperature hot water heating, steam

heating, warm air heating and central refrigeration plant.

U Ventilation / Air Conditioning System include toilet and kitchen extracts, smoke extracts

/ smoke control and various forms of air conditioning.

Pipe work generally

Pipes are classified under appropriate headings such as hot water supply and measured over

all fittings and branches in meters, stating the type, nominal size, method of jointing and type,

spacing and method of fixing supports, and distinguishing between straight and curved pipes

(SMM Y10.1.1.1.0 and Y10.M3). Pipes are deemed to include joints in their running length

(SMM Y10.C3) and the provision of everything necessary for jointing (SMM Y10.C1),

without the need for specific mention. The type of background to which the pipe supports are

fixed will be classified in the categories listed in SMM General rule 8.3.

Details of the kind and quality of materials used in the pipes, gauge and other relevant

particulars listed in SMM Y10.S1 6 are to be included in preamble clauses.

Made bends, special joints and connections and fittings such as Y-junctions, reducers,

elbows, tees and crosses are all enumerated as items extra over the pipes in which they occur

(SMM Y10.2.1 4). In the case of special joints, the type and method of jointing is to be

stated and they comprise joints which differ from those generally occurring in the running

length or are connections to pipes of a different profile or material, connections to existing

pipes or to equipment, appliances or ends of flue pipes (SMM Y10.D2).

Pipe fittings 65 mm diameters are classified according to the number of ends, while those

of larger diameter are described. The method of jointing is stated where different from the

pipe in which the fitting occurs.

Valves and cocks are classified as pipe work ancillaries and are enumerated, stating the type,

nominal size, method of jointing, type, number and method of fixing supports and the type of

pipe to be connected (SMM Y11.8.1.1.0). Those located in ducts or trenches are each kept

separate and so described.

Cutting holes through the structure for pipes and making good surfaces are enumerated,

stating the nature and thickness of the structure and the shape of the hole, classifying the

pipes as to size in accordance with SMM P31.20.2.1 3.2 & 4; for example pipes 55 mm

nominal size, 55 110 mm and > 110 mm.

Equipment

When measuring mechanical equipments, such details as type, size and pattern, rated duty,

capacity, loading as appropriate and method of fixing are stated. Specification cross

references are often inserted for mechanical equipment as provided for in SMM

Y20/40.1.1.1.0. Examples of equipments include boilers, generators, water treatment and

pressurisation plant, tanks, cylinders, clarifiers, pumps, compressors, fans, filters, humidifiers

and refrigeration units.

Air Duct lines

Ducting is classified as to whether straight, curved stating radii or flexible and giving the

type, shape, size, method of jointing and spacing and method of fixing supports, and

background, and is measured in meters (SMM Y30.1.1 5.1.1). It is measured over all

fittings and branches (SMM Y30.M3) and is deemed to include joints in running lengths and

stiffeners (SMM Y30.C3).

Items measured extra over include;

1. Lining ducting internally in meters, stating type and thickness of lining materials and

internal size of ducting (SMM Y30.2.1.1.0).

2. Special joints and connections, (SMM Y30.D2), enumerated stating type, size,

ducting size and method of jointing.

3. Fittings such as stop ends, bends, offsets, diminishing pieces, changes of section

pieces and junction pieces, access openings and covers for doors, nozzle outlets, and

test holes and covers are each enumerated stating the type (SMM Y30.3-6.1.1).

Ancillaries to ducting, such as grilles, diffusers, dampers, shutters, cowls, terminals, roof

ventilators, attenuators and anti-vermin screens are enumerated giving necessary information

(SMM Y30.4.1.1.0). Breaking in to existing ducting is given as item, stating the type, size

and location of duct and purpose of breaking in (SMM Y30.5.1.1 4).

Ducting sleeves are enumerated (SMM Y30.7.1 2.11 -2).

Pipe and Ducting Supports

Pipe and ducting supports which differ from those given with pipe or duct lines are separately

enumerated, giving details of the nominal size of pipe or shape and size of duct, type and size

of support, method of fixing pipe or duct support and nature of background (SMM

Y10.9.0.1.3 and Y30.6.0.1.3).

Builders work in connection with mechanical installations

Builders work in connection with a mechanical installation is identified under an appropriate

heading (SMM P31.M2). Unless identified in SMM work sections P30 and P31, all other

items of builders work are given in accordance with the appropriate work sections (SMM

P31.M1).

Example:

The example covers the measurement of low pressure hot water heating and ventilation

system. Refer drawing in page no 7.