by: shirley ho aedas ltd.: head of specification csi: professional member hkis: quantity surveyor...

By: Shirley HO Aedas Ltd.: Head of Specification

CSI: Professional Member

HKIS: Quantity Surveyor

Date: 27 August 2009

What a QS sees in Technical Specification?

Contents

• Function of technical specification • Difference between prescriptive

specification and performance specification • Knowledge and skills required to prepare

technical specification • How to prepare technical specification • Common problems & potential disputes

Tell the contractor

what you want

Specifications – Function

Bible Genesis 6:14-16:

Spec for Noah’s Ark• The vessel was to be made

with planks of gopher wood sealed with chemar.

• The ark was to be 300 cubits long, 50 wide and 30 deep.

• The ark was to have one door, built into its side, and a window. The inside of the ark was to be divided into three floors.

• It would house the 8 people, and the animals.



Let’s build an ark to save the

selected ones !

Noah, please build an ark like this:

1. gopher wood sealed with chemar

2. 300 x 50 x 30 cubits deep

3. XXX (i.e., SPECIFICATIONS !!!)

OK, Boss.


My Client wants to build

a house !

Contractor, please build a house like this:

1. Wood enclosure sealed with waterproofing

2. 300 x 50 x 30 m high

3. XXX (i.e., SPECIFICATIONS !!!)

OK, Boss.

Present written information that drawings cannot effectively

convey


DRAWING:

(Graphical)

• Design

• Location

• Dimension

• Quantity

Work Requirements – How to Describe?

What is this tile made

of?

This drawing may

look perfect, but does

it tell th

e full story?

If I cannot manufacture this tile in the exact dimension

as it is shown, by how much I can deviate?

Which color is this tile

in?


Concrete tile, XXXXX XXXXX XXX

Perhaps I can add a

lot of notes in this

drawing to tell the full

story?

Tolerance: XXX XXXX XXXXX XXXX XXX XXX XXX XXX XXX XXX

Color: XXXX

SPECIFICATION:

(Written)

• Materials

• Equipment

• Systems

• Standards

• Workmanship


It depends on how much the architect wants the contractor to

design.

Specifications – Prescriptive / Performance


100 kN Grade XXX

25mm thick

Say what it is

Performance Performance SpecificationSpecification

or

Say what it does

Prescriptive Prescriptive SpecificationSpecification

• Prescriptive: E.g.,

• proprietary product which has aesthetic requirement

• building structure

Specification Types – Design Extent Variance

• Performance: E.g.,

• waterproofing

• other concealed elements

Specification Types – Design Extent Variance

Similar to:

• Prescriptive Specification

• Prescriptive Specification

• More appropriate to show with Drawings

• Performance Specification


Bible Genesis 6:14-16:

Spec for Noah’s Ark• The vessel was to be made

with planks of gopher wood sealed with chemar.

• The ark was to be 300 cubits long, 50 wide and 30 deep.

• The ark was to have one door, built into its side, and a window. The inside of the ark was to be divided into three floors.

• It would house the 8 people and the animals.

Consider typical design process: e.g., drywall assembly


Restrictions Space available;

Regulation compliance

Objectives Performance (fire resistant, moisture resistant, acoustic requirement, etc);

Aesthetic requirement

Design intent Indicative solutions (overall profile, proposed material, etc)

Design check

Suitability & availability of proposed material;

Compatibility check

Detailed design

Fixing details;

Interfacing treatment;

etc

Performance Performance SpecificationSpecification








Design check


Compatibility check

Detailed design

Fixing details;


etc

Prescriptive Prescriptive SpecificationSpecification


100 kN

25mm thick

Prescriptive Prescriptive Specification:Specification:

Say what it is

Performance Specification:Performance Specification:

Say what it doesD

escriptive S

pecificatio

n

Descrip

tive Sp

ecification Grade XXX








Design check


Compatibility check

Detailed design

Fixing details;


etc

Descriptive Descriptive SpecificationSpecification

• Descriptive: E.g., Cladding wall system


aesthetic requirement

performance: loading, thermal insulation, etc

restriction

design intent

• Descriptive: E.g.,

• Window

• Operable wall


Who should prepare specification?

Specifications

Specifications – Who

Architect should prepare it because:• It is technical, it requires someone with

technical knowledge to write.

• It closely links with various parts of drawings which are prepared by architect. It also has to change in the same pace with changing drawings.

• It tests the practical feasibility of design done by architect.

• It provides an opportunity for architect to put in requirements which cannot be effectively illustrated by drawings.

Maybe you have confused these 2 kinds of specifications?

• Preliminaries Specification– It covers general

requirement. E.g.,• size and facilities of

site office• scaffolding• water & electricity

supply• as-built drawings

Specifications – Who

• Technical Specification– It covers technical

requirement. E.g.,• material and

product• workmanship• compliance with

international standards

• Sample & mockup

≠

Specifications – Knowledge & Skills Required

QS can prepare it because:• Technical knowledge can be acquired through working

experience.

• Coordination with drawings is similar to the preparation of BQ / SR.

• Practical feasibility test is similar to the process of understanding drawings in preparing BQ / SR.

• Writing skill, esp. precision, is a skill possessed by QS who prepares contract conditions, preliminaries specification, etc.

• Patience is a skill possessed by QS who prepares BQ / SR.

Systematically categorize information

Specifications – How

• NBS

• MasterFormat and MasterSpec

Specifications – Systematic categorization

Which type of specification?

Specifications

Sometimes it is better to share commonly used information …

Specifications – Which

Specification Types – Office-Wide or Not

Office-wide Specification

• Company-wide standard specification

• Each project specification is developed from this base

• Specific for each architectural firm



Advantages:

• Maintain a minimum quality for all project specifications

• Shorter time and less effort required for drafting project-specific specification

• Easier for inexperienced specification writer

• Allow updating of current code/standard reference

• If all project specification writers feed back to the office-wide keeper, previous error can be discovered & improved for whole company.



Disadvantages:

• Additional resource for maintaining a company standard

• On long term, specification writer becomes reliant on company standard, and loses ability to create specification on his own

• Office-wide specification contains more Material Codes than as called out by drawings of specific project

Spec Coverage – Office-Wide or Not

11:EQ7111:EQ71

05:AL2

09:CR92

08:CW11

09:P2409:P24

05:DM93

10:GR12

08:DH40

04:ST2504:ST2506:PL41

07:FG2207:FG22

10:OP13

04:MS1

07:JT5807:JT58

06:ML15

For Specific For Specific ProjectProject

Project-wide

part of project


Tailor-made Specification for Each Project

Advantages:

• Meet project specific needs

• Flexible in format

• Save effort in maintaining a company standard

• Learn from mistakes of previous projects


Tailor-made Specification for Each Project

Disadvantages:

• Take more time & effort to prepare for each project

• To save time & effort, one may attempt to copy & modify from previous projects’ specification, but this may inappropriately copy the project-specific requirement in previous projects’ specification

Sometimes it is better to share commonly used information …

Specifications – Which

Specifications – Standalone or Particular

Standalone Specification• Suffices on its own• Tailor-made for an

individual project • Simple interpretation: To

interpret the technical requirement of a project, one simply has to refer to one standalone document

Particular Specification• Supplement to a General

Specification• Modify, amplify and

update the contents of the General Specification as necessary to address the project-specific needs

• Complicated interpretation: To interpret the technical requirement of a project, one has to refer to multiple documents – Particular and General Specification

• General Specification

• For a particular jurisdiction, e.g., in Hong Kong: – Architectural Services Department

• For a particular owner , e.g., in Hong Kong – Hong Kong Airport Authority– Mass Transit Railway Corporation– Hong Kong Housing Authority

Specification Types – Standalone or Particular

Particular Spec

General General SpecificationSpecification

Specification Types – Standalone or Particular

Particular Specification

Advantages:

• Expected user is familiar with the General Specification, it saves time & effort to learn the full specification for each project

• Difference between 2 projects referring to the same General Specification can be easily spotted

• Maintain a minimum quality

• Serve as a safety net of supplementing necessary requirement missed in project specification

Critically analyze relevance of product information

Specifications – How

Specifications – Example

quality without specific standard reference

standard reference for

unknown quality

Brand A

• But we still need the following information about this Sports Floor:– What are the various components does it comprise?

– What material is it made of?

• If it is flammable, does it have any fire resistance quality? Has such quality been tested to any acceptable standards?

– Which kind of finish does it have?

– Regarding the mentioned shock absorption, deformation, friction, balls bounce, rolling load; exactly which DIN standard has been used to achieve the test result shown?

– About the mentioned BS 7044, what is the test result?

– Is there any special installation requirement?

– Does it come with a warranty? For how many years?



quality without

standard reference

selection factor

advertisementproduct’s restriction

Brand B

• But we still need the following information about this Mortar:

– What material is it made of? What is the proportion of various material in it?

– Regarding its rapid drying, low tension, high strength; has it been tested to any acceptable standards? What are the test results?

– Is there any special application requirement?

– Does it come with a warranty? For how many years?



aluminium

foil barri

er

Brand C

XXX

XXX

XXX

XXX

XXX

XXX

XXX

Common Terminology

Specifications

You have specified the size of tile,

so this tile is required to be 200.00mm by 200.00mm.

But in real world, it is impossible to fabricate 5000 pieces of this type of tile and each of them measuring exactly 200.00 x 200.00mm.

Specifications – Tolerance

200mm

200mm

If you insist on the specified size,

your specification becomes so unrealistic that nobody can possibly meet it.


200mm

200mm

Hence, you have to relax the size requirement.Yet you cannot allow the contractor to give you whatever size he likes.That’s why you permit some degree of deviation to control the actual size within an acceptable range:


Specified: 200mm

Permitted deviation: +/- 0.03mm

200mm + 0.03mm = 200.03mm

200mm - 0.03mm = 199.97mm

Obviously, site erection is inevitably imperfect, e.g., masonry wall:

Typically, its faces will not be perfectly flat & vertical, its position on plan will not be exactly as set out on drawings, its opening will not form a perfect rectangle, …


To address such imperfection, you may specify the tolerance from various angles:


Measurement Standard Tolerance (example)

Position on plan ± 10 mm

Length ± 15 mm

Height ± 10 mm

Level of bed joints (in any 5m) ± 10 mm

Straightness (in any 5m) ± 5 mm

Verticality (in any 3m) ± 10 mm

Verticality (in any 7m) ± 14 mm

Overall thickness ± 10 mm

Sample

•Verify visual appearance•Reference for controlling consistent standard

•Natural work range sample•Painting, etc applied on a simulated substrate•Indicate required size & quantity on specification

Specifications – Mockup, etc

Dimensional Mockup

•Full-scale three-dimensional model •Not actual materials•On-site or off-site •Confirm dimensional co-ordination•Indicate requirement on drawings


softwood post & frame

plywood wall

plywood box

chalk mark

plywood box

Mockup / Prototype

•Full-scale three-dimensional model•Utilise specified materials •On-site or off-site •Destructive test, not re-used as final work•Approval commence similar works at final location•Indicate requirement on drawings


Benchmark

•Complete part of similar works on site •Standard for checking quality of remainder of the similar works •Approval commence remainder•Protection•Indicate requirement on drawings


Standards & Test Values

Specifications

Specifications – Standards & Test Values

Common international standards

• British Standards or European Standards – BS (e.g., BS 952 or BS 476: Part 23)– BS EN (e.g., BS EN 179)– BS EN ISO (e.g., BS EN ISO 105)

• ASTM – ASTM A36– ASTM C509


Principle of reference standards

• Not stand alone as specification • Testing methods with established:

– test procedures– measurement standard– acceptable test values specified


Principles of reference standards

• E.g., BS 1230-1 - gypsum plasterboard


Principles of reference standards

• “Breaking load (transverse direction): Minimum 300N when tested according to BS 1230-1.”

Refer BS & say no further

minimum breaking load (260N) for 15mm thick board

• Inconsistency between technical specification and :– Another part of technical specification

• Between general & particular specification

– Drawings

– BQ / SR

• Unsaid requirement • Impossible requirement• Bad writing style

Specifications – Common Problems

Bad Writing Style

Specifications

Specifications – Writing Style

Unclear

• ambiguity

– “in a workmanlike manner” unenforceable term; it must always be necessary!

– “to the satisfaction of the architect” subjective, subject to abuse

– “shall function as intended” contractor has to hire a psychic to read the mind of the architect!

– “etc.”

• difficult for normal reader

• do not define all abbreviations

• inconsistent format font style & size, alignment, spacing, heading style, numbering system, etc.


Incorrect

• inaccurate• technically and grammatically incorrect• improper terminology• meaningless capitalization


Incomplete

• leave out anything that is important • achieve brevity at the expense of completeness• missing objects

– “as allowed” by whom?– “as appropriate” according to what?– “as approved” by whom?– “as directed” by whom?– “as indicated” where?– “as required” according to what or whom?– “as necessary” according to what or whom? - maybe

appropriate if a definition is specified that establishes the criteria for determining the necessity


Inconcise

• contain unnecessary words• not specific enough

– Example 1 - “… metal plate …”– Example 2 - “… steel plate …”– Example 3 - “… galvanized mild steel plate …”– Example 4 - “… Grade 316 galvanized mild steel plate

…”• conflicting terminology

– “supply and install” • Redundant -> always true unless otherwise

stipulated!


Concise

• No verbiage – well-crafted specification = the fewest words that

can be used to complete the description and make sense

Could we name proprietary products in specification?

Specifications

Specification – Naming of Proprietary Products

WTO’s restriction

• WTO: World Trade Organization • Agreement on Government Procurement (1994)

(GPA) • Principle: non-discrimination amongst products,

services and suppliers of a greater or lesser degree of foreign affiliation or ownership

• GPA “parties” are required to accord to the products, services and suppliers of any other “party” to WTO GPA treatment “no less favorable” than they give to their domestic products, services and suppliers


WTO’s restriction

• GPA “parties”: Canada, European Communities, Hong Kong, Iceland, Israel, Japan, Korea, Liechtenstein, Netherlands (Aruba), Norway, Singapore, Switzerland and United States – Hong Kong has committed to adhere to the WTO GPA since 20 May

1997

• procuring entities: relating to central government entities, sub-central government entities and other entities such as utilities

• construction services

• estimated value not less than 5,000,000 SDR (Special Drawing Rights) – Hong Kong @ 2006 and 2007: HKD57.636 million


• Some project clients may have their own established restrictions :– Some may promote non-discrimination in similar way as

WTO GPA– Some may promote protection for domestic products,

services and suppliers

• Always check with your own project client !!!

Besides WTO GPA, are there any other restrictions ?

Any Questions?

Specification for QS

Future Questions

Shirley Ho Aedas Ltd.: Head of SpecificationCSI: Professional MemberHKIS: Quantity Surveyor

(852) [email protected]

by: shirley ho aedas ltd.: head of specification csi: professional member hkis: quantity surveyor...

Documents

specifications function

xxxx slide

head of specification

noah s ark

xxxx xxxxx xxxx

xxxxx xxxxx

concrete tile

planks of gopher wood