Unit 6 Construction Information (Drawing, Detailing, Specification) LOl Evaluate different types of construction information in the context of diverse project types - Schedules & Specifications Schedules Within a construction project, many types of item may be used numerous times - they all fit within a general category but may have different types depending on their location and use. For example, there may be many different types of window in a project; some will be the same and others will be different, depending on their location, etc. Similarly, there will be different types of door, door handle, plumbing fixture, etc. In most cases, the individual items will be purchased (rather than made or built for the project) and we need a simple way to indicate where each specific type of item is to be used. Schedules A schedule is a table or list of the different items. Depending on the complexity of the project, we may need to identify different characteristics (height, width, thickness, colour, material, etc.) to differentiate the items. Alternatively, where the list includes pre-made items (from a single manufacturer or group of manufacturers), we may just need to give the manufacturer code and some basic information (type, finish). This information is coded in the list and the codes can then be cross• referenced with the drawings. When we need to install an item (a door, for example), we can find the code on the plan, look this up in the schedule, and know the specific type of door that is to be used. Schedules Some common types of schedule, used in coordinating with drawings, are: ► ► ► ► ► ► ► ► ► door schedules window schedules hardware schedules (e.g. door handles, window handles, etc.) finish schedules (types of paint, colour, ti ling, etc.) plumbing schedules (for large projects with many different plumbing fixtures). Individual activity What is the purpose of schedules? Why don't we just include all the information in the drawings? How does a bill of quantities differ from a schedule of works? What type of information are included in schedules? Schedules There are also other forms of schedule that may comprise part of the construction information. These may be used when quantifying materials and costs, for example: ► a schedule of rates shows the costs associated with specific types of construction work ► a schedule of works is a table listing the different types of work to be undertaken in a project (this is more commonly used in smaller projects) ► a bill of quantities (BoQ) lists the measured quantities required for the `different works identified in a project ► a schedule of services lists the specific services to be provided contractor or consultant. by a Specifications The specification is a written document (or, for large projects, a series of documents) describing in detail the scope of work, materials to be used, methods of installation, and quantity of workmanship with reference to established standards in the construction industry.for a parcel of work to be placed under contract. It is usually utilized in conjunction with working (contract) drawings in building construction. Specifications do not include information about cost or quantities; this information will be compiled in related schedules, drawings and contract documents. In some cases, the specification will include information about specific products and suppliers, or it may describe items in relation to their expected characteristics (performance). Specification vary considerably depending on the stage to which the design has been developed, ranging from performance specifications (open specification) that required further design work to be carried out, to prescriptive specifications (closed specifications) where the design is already complete. Who uses Specifications? Pre contract: •Part of the design brief process •Cost control team •Contractors estimating team During contract: •Site agent and operatives •Clerk of the works Post contract: •Design record •Evidence in disputes +FM Specifications – Content Design requirements - what needs doing Details of the materials to be used Performance specification - how it is to be done The extent of works to be carried out •The quality and type of materials to be used •The standards of workmanship that will be acceptable •The specification does not instruct the contractor how the work is to be done rather describes what must be achieved in terms of quality. Characteristics of a Specification • have a logical layout The layout of the Specification should follow a logical order and be simple to use. The order of the clauses should follow the 'Standard Method of Measurement'. • be complete There should be no missing items and the descriptions given should need no further clarification. (When read in conjunction with the drawings) • be concise There should be no redundant information should be avoided. material. In particular, repetition • be clear and precise The clauses should be written in clear, unambiguous language that is not open to misinterpretation. This is a very difficult task. Historically. Architects I Engineers will interpret clauses differently from building contractors. This has led to much dispute and litigation. • be cross checked with the other contract documents The Specification must not contain any information that conflicts with information shown on the contract drawings or schedules. Any conflicts can lead to costly disputes. of Types of Specification There are different types of specification that may be used: The first stage in the development of a specification is the preparation of an outline specification. An outline specification is a brief description of the main components to be used in construction. They should be described in sufficient detail to allow the cost consultant to prepare some approximate quantities. An outline specification is a description of the main elements to be used in the construction. Each element will be described at a level of detail that allows the cost consultant to provide approximate quantities and costs. Types of Specification ► Performance specifications are commonly used in projects that are relatively standard or straightforward. This type of specification describes what the various elements must do (their performance) and allows the contractor to determine what materials and systems may be used to provide the expected performance need. Performance specification - don't identify a brand, just the performance characteristics. ■ This gives greater freedom to the contractor and can reduce the cost as a cheaper alternative is found. ■ The designer must check that the material used complies with the specification. It gives contractor flexibility in his construction approach and limits how much authority an architect maintains once construction is underway. The nature of the performance required may be defined by the desired outcome or reference to standards such as NBS. Specifications ► Prescriptive specifications (or full/Close specifications) are the most detailed. They are commonly used on projects which have very specific requirements, either from the client or due to the nature of the project. For example, a high-level containment laboratory (for working with very contagious diseases) will have very strict requirements for nearly every aspect of the project. In this case, the specification will prescribe many of the materials, systems and processes to be used to construct the facility. Similarly, a high-end apartment building (which will have very expensive apartments) may have very particular requirements from the designer and client, in terms of materials and finishes. Prescriptive specification - gives clear details about the exact product required. ■ This will link to the performance criteria of the product. ■ Often the words 'or equal approved' & 'or equal' are used. Specifications Prescriptive specifications typically provide detailed description of what specific materials must be used as well as the installation instructions. This type of specification usually involves three key components: • General provisions: requirements surrounding codes and standards which may include information about specific types of material, suppliers, finishes, etc. • Required products: the types of products required based on performance and structural stipulations, provisions may include door hardware, kitchen equipment, furniture, lighting, etc. • E x e c u t i o n p r o c e d u r e s / construction/installation methods - the client team (client/ architects/designers) may specify how custom- designed items are to be manufactured and installed, to ensure the quality of the final outcome. Prescriptive specifications put a greater burden on the architect (as opposed to the contractor) to ensure proper installation. Proprietary Specifications demand that only one specific product be used for a given installation. It is commonly utilized if the portion of a project requires a certain performance that only one product can achieve. This could ultimately drive up project costs. Specification clauses All Specifications are made up of many clauses. Each clause should be written in a standard way starting with a general description of the work item followed by more detailed information. Simple descriptions should be used using everyday language. Certain types of description should be avoided altogether, such as: "finest quality" " 4 . nm to th us·f;ac·v+o :he A\r, cn·Aiir4ecst4,s sa·# ¢ Specification clauses Specifications can be written in various ways, for example: 1. The Specification is divided into two parts: • The' Materials Section' - giving exact descriptions of all the materials to be used, with reference to the relevant British Standards • The 'Workmanship Section' - describing exactly how the materials should be handled and used, with reference to any applicable BS Codes of Practice. This method is commonly used for Civil Engineering Works 2. The Specification is divided into trades. Each trade is then dealt with separately with a section covering both materials and workmanship. This method is commonly used for Building Works 3. The Specification is divided into trades. Each trade is then dealt with separately with separate sections covering materials and workmanship. E.g.: (a) Concrete work (i) materials (ii) workmanship (b) Brickwork and Blockwork (i) materials (ii) workmanship Specifications Specifications can be very complex documents, and their role in describing the project means they have considerable importance throughout the project. Their role (along with drawings and schedules) in establishing project costs during the tender process requires them to be as accurate as possible. There are standard forms of specification compiled by different industry bodies, to standardise both the language and the use of specifications. In many instances, complex templates or software suites are available to support specification writers to develop clear, precise, standard specifications. Some of the standards that are available include: • National Building Specification (NBS) - UK • MasterFormat (CSI) – USA • NATSPEC – Australia Class discussion Describe specifications Discuss the importance of specification for a project What are the difference between outline, descriptive, prescriptive and propriety specification.
