Lecture 10 – Specifications for Building Works

Definitions

  • Specification: detailed description of how something should be done or made.
    • Cambridge: “A detailed description of how something should be done, made, etc.”
    • Merriam-Webster: “A detailed description of work to be done or materials to be used in a project: an instruction that says exactly how to do or make something.”
    • BusinessDictionary: “Exact statement of the particular needs to be satisfied, or essential characteristics that a customer requires … and which a vendor must deliver.”
  • CIOB / Designing Buildings Wiki definition:
    • Describes materials and workmanship required.
    • Excludes cost, quantity, drawn information.
    • Must be read with quantities, schedules, drawings.
    • Range: performance (open) ↔︎ prescriptive (closed).

Types of Specifications

  • Open / Performance Specifications
    • Further design work required.
    • Greater scope for supplier innovation.
    • Suitable for straightforward & well-known building types.
  • Closed / Prescriptive Specifications
    • Design already complete.
    • Client gains greater certainty on end-product.
    • Used for specific or specialist products.
  • Most projects combine both types.

Responsibility for Specifying

  • Possible authors:
    • Client (may procure certain products competitively).
    • Consultant (experience with particular products).
    • Contractor (buildability considerations).
  • Specification development runs in parallel with design.
    • Two main parts: Products & Workmanship.
    • Should be structured by work packages.

Functions of Specifications

  • Information system that:
    • Describes requirements & intent of works.
    • Referenced by tenderers for pricing.
    • Serves as supervising document on site.
  • Records quality of materials & workmanship where drawings insufficient.
  • Vital in Contracts without Quantities; supplemental to Bills of Quantities (BQ) in Contracts with Quantities.

Specification Principles

  • Draw what can be shown; schedule/specify the rest.
  • Avoid duplicating drawings within specs.

Core Contents

  • Materials descriptions (bricks, cement, sand, timber, etc.).
  • Workmanship quality (e.g.
    • Concrete mix proportions).
  • Description of work locations/types (mass concrete vs RC, etc.).
  • Sizes & positions of lintels, timbers, finishes.
  • Exact construction methodology.

Preparing Specifications

  • Architect/designer must convey intent precisely; remove vagueness.
  • Essential practices:
    • Know practical construction.
    • Visualise the work.
    • Think like an estimator so no doubts remain.
    • Remember role as client’s agent regarding expenditure.

Requirements of a Good Specification

  • Correct formatting.
  • Language clear, concise, explicit, free of irrelevant matter.
  • Use universally-accepted technical terms.
  • Internal consistency.
  • Completeness—omit nothing.

Users of Specifications

  • Contractor, Estimator, Site Agent: pricing, procurement, construction.
  • Architect & site representatives: submission approvals, supervision.
  • Quantity Surveyor: cost estimates, BQ preparation.
  • Engineers (C&S, M&E) & resident staff.

Specification Writers – Qualifications & Candidates

  • Need familiarity with project & design philosophy.
  • Editorial, technical, contractual expertise.
  • Availability & willingness.
  • Likely writers: Architect, Architect’s assistant, Quantity Surveyor, Engineers, Specialist suppliers.

Origin of Specifications in Malaysian Contracts

  • Example: PAM Contract 2006 (Without Quantities)
    • Contract Documents include: Letter of Award, Articles, Conditions, Drawings, Contract Bills (with Preambles & Specification), etc.
    • Contract Bills list: Instructions to Tenderers, Conditions of Tendering, Form of Tender, Preliminaries, Preambles & Specification, Schedule of Rates, etc.

Malaysian Standard Specifications (JKR)

  • "Standard Specifications for Building Works" (2005 Ed.)
    • Sections A–N covering Preliminaries, Piling, Excavation, Concrete, Brickwork, Drainage, Roofing, Carpentry & Joinery, Structural Steel & Metal Works, etc.
  • Example extract – Section D: Concrete Works
    • Cement options: Ordinary, Rapid Hardening, Sulphate Resisting, Pulverized-Fuel Ash, Slag.
    • Certificates of test required; additional lab tests for suspect batches.
    • Target mean strength:
      \text{Target} \ge \text{Grade} + 1.64\sigma
      with minimum margins 2.5\text{ N/mm}^2 (Grade 15) or 3.75\text{ N/mm}^2 (Grade 20+) using 100-batch data; higher minima with 40-batch data.

Case Study – Hot-Dip Galvanised Steel (Roof Steel Structure)

  • Process: pass steel through molten zinc at 460\,^{\circ}\text{C} (≈860\,^{\circ}\text{F}).
  • Benefits: rust resistance; spangled surface; critical for coastal areas.
  • EN ISO 1461:1999 coating weights (minimum averages):
    • Thickness ≥ 6\,\text{mm}: 610\,\text{g/m}^2 (≈85\,\mu\text{m}).
    • 3–6\,\text{mm}: 505\,\text{g/m}^2 (≈70\,\mu\text{m}).
    • 1.5–3\,\text{mm}: 395\,\text{g/m}^2 (≈55\,\mu\text{m}).
  • Atmospheric durability depends on contaminants, chlorides, climate.
  • Industry references: Galvanizers Association of Australia, UK, Asia.

Drawing & BQ Integration (Project Example – RMN Culinary Building, Lumut)

  • Drawings to carry the note: “All steelwork for roof steel structure – to be hot-dip galvanised.”
  • Bill of Quantities likewise to state hot-dip galvanising requirement.
  • Sample BQ item: Design, erect & complete prefabricated galvanised roof trusses (≈942\,\text{m}^2 including purlins, rafters, I-beams, fasteners, anti-rust paint, etc.).

Structural Steel & Metal Works Specification (Section I excerpt)

  • Conform to JKR 20600-0019-99 and BS 5950.
  • Materials: H-Sections, channels, plates per JIS G3192, etc.
  • Contractor’s design submission requirements: design plan, verification, software validation, transport method statement, design review report.
  • Workmanship: welding per BS 5135/4570; independent welding inspection (SIRIM/CIDB certified).
  • Protective treatment: Section 10 – cleaning, coating, galvanising.
    • Galvanising per BS 729 (superseded by BS EN ISO 1461 : 2009).
    • Touch-ups allowed for areas within 10\,\text{mm} of intact coating; min. repaired thickness 100\,\mu\text{m} unless agreed otherwise.
  • Fire protection materials must meet \text{BS 476} tests & be endorsed by Jabatan Bomba.

Contract vs Specification

  • Building Contract Types:
    1. With Quantities (BQ-based)
    • Contractor prices from BQ; may rely less on drawings.
    • BQ must be fully detailed & specified.
    1. Without Quantities (Specification + Drawings)
    • Lump-sum bid based on detailed spec & drawings.
    • Provisional allowances may cover unforeseen items.
    • Suitable for smaller projects & extensions.

Pros & Cons – Contract Without Quantities

  • Advantages
    • Firm lump-sum price; avoids client risk of BQ errors.
    • Can incorporate design-and-build or performance specs.
  • Disadvantages
    • Design must be advanced → later site start.
    • Less cost control when variations occur (no defined measurement system).
    • Tenders harder to compare; each contractor measures & prices risk differently.
  • Consequences of incomplete drawings/specs
    • Tenderers may refuse or price high for uncertainty.
    • Higher likelihood of disputes & variations (>15\% VO indicates poor practice).
    • Potential additional client cost and contractual conflict (Willis & Willis 1997).

Ethical & Practical Implications

  • Clear, complete specs reduce contractual disputes and protect client interests.
  • Integration with BIM, CAWS, BoQ enhances coordination.
  • Encourages industry innovation (open specs) while ensuring safety & performance (closed specs).

Key Standards & References Mentioned

  • JKR “Standard Specifications for Building Works” (2005).
  • JKR Standard Specification for Structural Steelwork No. 20600-0019-99.
  • BS 5950 (Structural steel design).
  • BS 5135, BS 4570 (Welding).
  • BS 729, BS EN ISO 1461:2009 (Hot-dip galvanising).
  • BS 476 (Fire testing).
  • CAWS, Bill of Quantities, BIM guidance.

Summary

  • Specifications articulate the qualitative essence of building works—materials, workmanship, performance—complementing drawings, quantities, and contracts.
  • Their accuracy, clarity, and completeness critically influence pricing, construction quality, legal compliance, and project success.