About Specification and Estimating

1. Importance and formulation of
Specifications and Estimations
Shish Haider Chowdhury ndc, MCIPS
Joint Secretary
Ministry of Public Administration
BIAM, 5 November 2021

2. Specifications
 Specification (often abbreviated as spec) is an
explicit set of requirements to be satisfied by a
material, product, or service.
 A type of technical standard.
 Should a material, product or service fail to meet
one or more of the applicable specifications.
Defined

3. Specifications
• The Contract Specifications are essential for
complete understanding of theWork to be
performed by the Contractor.
• The Architect/Engineer should be just as skilled in
preparing the Specifications as in preparing the
Drawings

4. Importance of Clear Specifications
• Risks Controlled – to ensure product/service is
delivered as required.
• ObtainValue for Money - allows vendors to
evaluate and respond efficiently and with assurance
• Maximises success – true and accurate statement of
the buyer’s requirements improves the entire
purchasing process.

5. Kinds of Specification
• Formal specification
• Program specification
• Functional specification
• Web service specification
• Document specification

6. Technical Specifications
 To provide clear unambiguous and standard
descriptions
 To enable evaluation against defined criteria
 To promote wider competition
Main Purpose

7. Aims inWriting Specifications
 Provide enough information for suppliers to decide
cost
 Permit evaluation against stated criteria
 State acceptance requirements (tests etc.)
 Contain only essential features required
 Provide equal opportunity to all suppliers
 Provide opportunity for alternate technology where
appropriate
 Comply with legal and Entity requirements

8. Information in Specifications
Rule - 29 PE shall provide following information
 Name or description of the Goods,Works or Services to be
procured;
 Required performance Standards and life span;
 Quality of Goods,Works or Services;
 Safety Standards and limits;
 Symbols, terminology to be used in packaging, marking and
labelling;
 Processes and methods to be used in the production of goods,
where applicable; and
 Test procedure, if any, for conformity assessment.

9. Specifications should be
 Expressed in terms of performance or output requirements rather
than specifications directly linked to design or descriptive
characteristics, which usually tend to limit competition R-29(2)(a)
 prepare the specifications in close cooperation with the concerned
user or beneficiary and follow, among others, the Standards
approved or published by -ISO, IEC, & the Bangladesh Standards
&Testing Institute (BSTI) or any other national or international
institute R-29(5)
Rule - 29

10. Trade Mark etc.
 No reference to a particular trade mark or trade name,
patent, design or type, specific country of origin,
producer or service supplier R-29(3)
 If a PE does not have adequate technical expertise for
preparingTS to make it fully understandable to
Tenderers, it can make a reference to a particular
brand, but in such case shall add the words, “or
similar or equivalent” R-29(4)
Rule - 29

11. Technical Specifications
Design Based Specifications:
 Lays down the detailed designed drawings, material specifications, bill of
quantities, etc.
 Used for civil works, and expensive unique plant and equipment including
installation.
Performance Based Specifications:
 Lays down capacity and performance for a specific purpose.
 Used for defining the output of mass produced capital goods; such as highway
maintenance equipment, generators, transformers, etc.
Physical Property Based Specifications:
Used for metals, commodities, hardware, pipes, cables, rails.
Types

12. Performance based specifications
 Description ofWork
 Output required (in amount and quantity)
 Quality & Performance Standards
 Measurement of Performance
 Ancillary services required

13. Writing Specifications
Continuous liaison between User, Specification Writer (Expert),
Procurement Staff (PE) and the Market Place.
User Draft Procurement
Administration
Acceptable?
Specification
Writing
Acceptable to
All Parties
Specification
Issued
Producers
Information,
Standards
etc.
Refer to User
Refer to User
Refer to Procurement

14. Writing Specifications (Cont’d)
 Use simple language
 Define terms/acronyms
 Must be easily readable
 Must have logical structure
 Short paragraphs
 Attractive layout
 Systematic Numbering
 Ensure good grammar
 Readable by non-specialist
When Writing Do …….

15. Writing Specifications (Cont’d)
 Use complicated language (jargon/undefined terms)
 Be vague
 Be too exact
 Over specify
 UseTrade or Brand names
 Use unnecessary standards
 Conflict with other documents
 Provide unnecessary information
When Writing DO NOT …….

16. Elements of Specifications
Function
Purpose
Technical
Aspects
Need
Performance
Characterised
By

17. Road Roller Specifications
Test?
Static Linear Pressure: Average static linear load
should be
i) Front Roll
With Ballast: 310 N/cm2 (minimum)
ii) Rear Roll
With Ballast: 410 N/cm2 (minimum
Load?
Performance Aspects?

18. Road Roller Specifications
Speed?
Travel Speed:
i) More than two speed transmission
(forward & reverse)
ii) Upper Limit ofTravel Speed : 14
km/hr (minimum)
Brake System:
Service Brake: Hydrostatic
Parking Brake: Hydro-mechanical
emergency stop device.
Break ?
Functional Aspects?

19. Road Roller Specifications
Element
Material
Manufacture
Fixture
Standards
Engine:
Rated Power:The engine should be
capable to produce minimum 60 kw at
its constant operating speed of 2400
rpm (minimum).
Scraper: Scraper must be fitted for
each roller drum on both sides.
Technical Aspects?

20. Environmental Requirement
 Environmentally friendly equipment and
Specifications
 Minimum pollution in use or disposal
 Energy efficiency and future demands
 Support equipment and future availability
 Third party support and development

21. Social and Other Factors
 Public acceptability
 Employment effects and Labour
generation
 Life Span costs and commitments
 Information sources
 Public image
 Political implications

22. Good Specifications
State the requirement clearly, logically,
unambiguously and comprehensively
Allow potential suppliers to decide and cost
their offer
Enable evaluation against defined criteria
Provide equal opportunity for all suppliers
Comply with all necessary legal obligations and
certification
Major Elements

23. Estimation
Estimation is the scientific way of working out the
approximate cost of an engineering project before
execution of the work.
 It may differ from the calculation of the exact cost
after completion of the project.
 Estimation requires a thorough knowledge of the
construction procedures, cost of materials & labour in
addition to the skill, experience, foresight and good
judgment.

24. Estimate
An estimate of the cost of a construction job is the
probable cost of that job as computed from plans
and specifications.
For a good estimate the actual cost of the proposed
work after completion should not differ by more than 5
to 10 % from its approximate cost estimate.

25. Units of Measurement
The units of measurements are mainly categorized for their
nature, shape and size and for making payments to the
contractor.
a) Single units work like doors, windows etc, is expressed in numbers.
b) Works consists linear measurements involve length like cornice,
fencing, hand rail etc., are expressed in running meters (RM)
c) Works consists areal surface measurements like plastering, white
washing, partitions of specified thickness etc., are expressed in
square meters.
d) Works consists cubical contents which involve volume like earth
work, cement concrete, Masonry etc., are expressed in Cubic meters.

26. Need of Estimation and Costing
∙ It help to work out the approximate cost of the project in order to
decide its feasibility with respect to the cost and to ensure the
financial resources.
∙ Requirements of controlled materials, such as cement and steel
can be estimated.
∙ It is used for framing the tenders for the works and to check
contractor’s work during and after the its execution for the
purpose of making payments to the contractor.
∙ From quantities of different items of work calculated in detailed
estimation, resources are allocated to different activities of the
project and ultimately their durations and whole planning and
scheduling of the project is carried out.

27. Data required to prepare an estimate
 DRAWINGS: If the drawings are not clear and without
complete dimensions the preparation of estimation
become very difficult. So, it is very essential before
preparing an estimate.
 SPECIFICATIONS
• General Specifications: This gives the nature, quality of work
and materials in general terms to be used in various parts of
wok. It helps to form a general idea of building.
• Detailed Specifications: This gives the detailed description of
the various items of work laying down the Quantities and
qualities of materials, their proportions, the method of
preparation workmanship and execution of work.

28.  RATES
For preparing the estimate the unit rates of each item of work are
required.
•For arriving at the unit rates of each item.
•The rates of various materials to be used in the construction.
•The cost of transport materials.
•The wages of labor, skilled or unskilled of masons, carpenters, Amador,
etc.,
LUMPSUM
While preparing an estimate, it is not possible to work out in detail in
case of petty items. Items other than civil engineering such items are
called lump sum items or simply LS Items.
Data required to prepare an estimate (Cont’d)

29. Factors to be considered for estimation
 Each type of work requires a different method of construction.
Construction may be of an ordinary house or office and it may
also be of a Dam, Tunnel, Multistory building, Airport, Bridge, or
a Road, already in operation. Each of these works requires
totally different construction techniques, type of machinery, and
formwork.
 Quality of labour and labour output varies in different localities.
 Weather conditions greatly affect the output and, hence, the
overall cost.

30. Factors to be considered for estimation (Cont’d)
 Ground conditions vary and change the method of
construction. For example, excavation may be dry, wet, hard,
soft, shallow or deep requiring different efforts.
 The source of availability of a sufficient supply of materials of
good quality.
 The availability of construction machinery also affects the
method of construction.
 Access to the site must be reasonable. If the access is poor,
temporary roads may be constructed.

31. Types of Estimate
There are two main types of estimates:-
 Rough (or) approximate estimate.
 Detailed estimate.

32. Rough (or) approximate estimate
 Preliminary or approximate estimate is required for
studies of various aspects of work of project and for its
administrative approval.
 It can decide, in case of commercial projects, whether
the net income earned justifies the amount invested or
not. The approximate estimate is prepared from the
practical knowledge and cost of similar works.
 The following are the methods used for preparation of
approximate estimates.
• Plinth area method
• Cubical contents methods
• Unit base method.

33. Detailed Estimate
 Detailed estimates are prepared by carefully and
separately calculating the costs of various item of the
work that constitute the whole project from the detailed
working drawings after the design has been finalized.
 The mistakes, if any, in the rough cost estimate are
eliminated in the detailed estimate.
 Detailed estimates are submitted to the competent
authorities for obtaining technical sanction.