The structure of information

Monr\i«.#) / IW bnooght a set of i*-»*" n6w wovWg ¿yaioiwgs

¡a a-ccovdaiAce to'M the latest foritiiU Sfc&ncUrdL ...

mprtvê speed, tW. efficiehc^ , wot to ivientioirt. co^Mu^it^t'co^i. c ! Wtiki: /Voco hiik fa i»y"ràiSoy> cPefre cretftvt design// \ 11 i | A

mprtvê speed, tW. efficiehc^ , wot to ivientioirt. co^Mu^it^t'co^i. c ! Wtiki: /Voco hiik fa i»y"ràiSoy> cPefre cretftvt design// \ 11 i | A

1.1 Hellman's view of the problem

Let \Mt «./plfe'i*—Pir^t -you ^ive AI location pl^ns on a ^b&ntL-fcvd. 'Hi/ft dii-t^steHft.1 o/r;«L ui'tfh codes i- s.yvwbote ireUt'.^a ScAWyje-S efc ek ..,

•fV«?»*. ukcU >joo re-feir +o A4- A^e^by sefcs,ktom *Woe-&te«(. co<Ae\ -fov cokfouewb scteiUes Yt-tevriA/)

secondSchedules -frow^ loW&U

■fini, fcke reliV^t COh«w«it dLvdW.rtAS oW oW___—---— J

Let \Mt «./plfe'i*—Pir^t -you ^ive AI location pl^ns on a ^b&ntL-fcvd. 'Hi/ft dii-t^steHft.1 o/r;«L ui'tfh codes i- s.yvwbote ireUt'.^a ScAWyje-S efc ek ..,

■fini, fcke reliV^t COh«w«it dLvdW.rtAS oW oW___—---— J

1.1 Hellman's view of the problem

The problem

No one who has delivered drawings to site and overheard the foreman's jocular reference to a 'fresh set of comics' having arrived will deny that the quality of architects' working drawings in general is capable of improvement. In some measure we have all of us suffered more or less justifiable accusations of inaccuracy, inadequacy and incomprehensibility; and yet drawings are prepared and issued with the best of intentions. Few offices deliberately skimp the job, despite economic pressures and time constraints, for the consequences of inadequate or incorrect information being passed to the builder loom frighteningly behind every contract. We do our genuine best, and still things go wrong which might have been avoided; still information is found to be missing, or vague, or incorrect (1.1).

UCD JMKt-t

Mr jcaionj- or Yin/taic i—i—1—'—i—i—i—±

UCD JMKt-t

Mr jcaionj- or Yin/taic i—i—1—'—i—i—i—±

mm mm>

The 1973 UK Building Research Establishment's paper 'Working drawings in use' lists a depressing number of defects which the authors found giving rise to site queries. Those defects include:

• unco-ordinated drawings (ie information from different sources found to be in conflict)

• errors—items of information incorrect

• failures in transmission (ie information produced and available but not put in the right hands)

• omissions—items of information accidentally missing

• poor presentation (ie the drawing or set of drawings was complete, but confusing to read).

Analysis of this list suggests that the defects spring from different causes—some from an inadequate understanding of the users' needs, some from an indisciplined approach to the problems of presenting a complex package of information, and some from faulty project management procedures. That the problems seem to arise more frequently in relation to architects' drawings than to these of other disciplines merely illustrates how the difficulty is compounded by the complicated nature of the architect's work and the diversity of the information he has to provide. The structural engineer need only adopt a simple cross-referencing system to enable him to link any structural member back to a general arrangement drawing; but for an architect economically to give precise and simply understood directions about, say, a door set—involving a range of variables which include door, frame, architrave, finishes, materials and ironmongery—a communications method of some complexity will be required. Where is such a method to be found? (1.2)

Problems of communication

The Handbook of Architectural Practice and Management (published by the Royal Institute of British Architects)

1.2 House at Gerrards Cross by A. Jessop Hardwick, c. 1905. A typical working drawing of its era, in both its draughting techniques, and its obsessive use of every inch of the drawing sheet (RIBA Drawings Collection)

points out, 'As with all technical communication, the user's needs are the prime consideration'. Whoever the user is—and the users of a set of drawings will be many and various—he has the right to expect that the information given to him will be:

• an accurate record of the designer's intentions

• clearly expressed and easily understood

• comprehensive and sufficiently detailed for its purpose

• easily retrievable from the mass of other information with which, inevitably, it will be combined.

It is the purpose of this book to consider these four requirements in detail and hopefully to propose techniques for satisfying them.

There is a fifth and fundamental requirement, of course. The information conveyed must be technically sound, and if this is not the case then all the careful draughting and cross-referencing will not be sufficient to prevent disaster. This aspect, however, lies outside the scope of the present book which must concern itself only with the adequate documentation of technical decisions already made at an earlier stage. In RIBA Plan of Work terminology, the decisions belong to stage E; their documentation belongs to stage F.

The plan of work

Since what we shall be looking at is in effect a series of disciplines, and since the plan of work is the overriding discipline into which the working drawing process is integrated, it is probably worthwhile reminding ourselves of the plan of work at the outset. Table I shows it in its entirety, with descriptions of its elements simplified somewhat from the original in the interests of brevity.

Frequent reference to the plan of work will be made in this book, for it is important that stage F production drawings should be seen in the context of the whole architectural process, forming the vital link between the designer's intention and the builder's execution of it. The successful implementation of many of the techniques to be dealt with here will depend upon proper procedures having been carried out at earlier stages, whilst the whole raison d'être of the drawing set lies in the stages following its production.

A point of some importance should be noted here, one which is often overlooked by student and busy professional alike. The working drawing set is for building from. Its destined homes are the building site and the craftsman's workshop. A working drawing carrying extraneous information—motor vehicles

Table I The RIBA outline plan of work immaculately added by stick-on film, little pedestrians walking past elevations to give the scale—is overloaded and unprofessional, giving an instant impression of having been prepared by someone who was not quite sure what was required of him.

So, no decorative blandishments. (If only because if you insist on adding shadows to your elevations it will only be a matter of time before the site office telephones to ask what colour brick you want them built from).

Stage Purpose of work and Tasks to be done People directly Usual

Decisions to be reached involved Terminology

A. Inception To prepare general outline of Set up client organisation for All client Interests, Briefing requirements and plan future briefing. Consider requirements, architect, action. appoint architect.

B. Feasibility To provide the client with an appraisal and recommendation in order that he may determine the form In which the project is to proceed, ensuring that it is feasible, functionally, technically and financially.

Carry out studies of user requirements, site conditions, planning, design, and cost, etc., as necessary to reach decisions.

Clients' representatives, architects, engineers, and QS according to nature of project.

C. Outline To determine general approach

Proposals to layout, design and construction in order to obtain authoritative approval of the client on the outline proposals and accompanying report.

Develop the brief further. Carry out studies on user requirements, technical problems, planning, design and costs, as necessary to reach decisions.

All client Interests, architects, Sketch engineers, QS and specialists Plans as required.

D. Scheme To complete the brief and decide

Design on particular proposals, including planning arrangement appearance, constructional method, outline specification, and cost, and to obtain all approvals.

Final development of the brief, full design of the project by architect, preliminary design by engineers, preparation of cost plan and full explanatory report. Submission of proposals for all approvals.

All client interests, architects, engineers, QS and specialists and all statutory and other approving authorities.

Brief should not be modified after this point.

E. Detail To obtain final decision on every

Design matter related to design, specification, construction and cost

Full design of every part and component of the building by collaboration of all concerned. Complete cost checking of designs.

Architects, QS, engineers and Working specialists, contractor (if Drawings appointed).

Any further change In location, she, shape, or cost after this time will result in abortive work.

r. Production Information

To prepare production information and make final detailed décidons to carry out work.

Preparation of final production Information I.e. drawings, schedules and specifications.

Architects, engineers and specialists, contractor (If appointed).

e. Bin« of Quantities

To prepare and complete all information and arrangements for obtaining tender.

Preparation of Bills of Quantities and tender documents.

Architects, QS, contractor (If appointed).

H. Tender Action as recommended In NJCC

Action Code of Procedure for Single Stage

Selective Tendering 1977.*

Action as recommended In NJCC Code of Procedure for Single Stage Selective Tendering 1977.*

Architects, QS, engineers, contractor, client.

J. Project To enable the contractor to

Planning programme the work in accord ance with contract conditions ; briefsiteinspectorate;and make arrangements to commence work on site.

Action in accordance with The Management of Building Contracts" and Diagram 9.

Contractor, sub-contractors.

Site

Operations

K. Operations on Site

To follow plans through to practical completion of the building.

Action in accordance with The Management of Building Contracts" and Diagram 10.

Architects, engineers, contractors, subcontractors, QS, client.

L. Completion

To hand over the building to the client for occupation, remedy any defects, settle the final account, and complete all work in accordance with the contract.

Action in accordance with The Management of Building Contracts" and Diagram 11.

Architects, engineers, contractor. QS, client.

M.Feed-Back

To analyse the management, construction and performance of the project

Analysis of job records. Inspectlonsof completed building. Studies of building in use.

Architect engineers, QS contractor, client.

*The publications Code of Procedure for Single Stage Selective Tendering (NJCC 1977) and Management of Building Contracts (NJCC 1970) are published by RIBA Publications Ltd for the NJCC.

The users

There are many users of a set of drawings and each may put it to more than one use. Unless the set is to be redrawn expensively to suit the ideal requirements of each, then priorities must be established and compromises accepted. Consider the following functions of a set of drawings (the list is by no means exhaustive). It forms for different people and at different times:

• a contractual commitment

• a source for the preparation of other documents

• a statement of intent for the purpose of obtaining statutory consents

• a framework for establishing nominated sub-contractors or suppliers

• a source for the preparation of shop drawings

• a shopping list for the ordering of materials

• a construction manual

• a model for developing the construction programme

• a supervising document

• a record of variations from the contract

• a base document for measurement of the completed works and preparation of the final accounts

• a base document for defects liability inspection

• a record of the completed structure

It will be noted that the majority of these uses involve the contractor and clearly his needs are paramount, if only for the purely legal reason that it is he who will be contractually committed to the employer to build what the architect tells him to. They may be separated into three main activities, and any drawing method must satisfy all three if it is to prove viable.

Activity 1 The procurement of all the necessary materials and components. For this he will need the following information in a form in which it can be identified readily and extracted for ordering purposes:

A specification of the material to be used, which can be referred back simply to the drawings and the bills of quantities.

Drawings and schedules of all components which he is to provide (doors, windows, etc), and which constitute measured items in the bills of quantities. Drawings and schedules from which outside manufacturers' products may be ordered, and which provide design criteria against which manufacturers' shop drawings may be checked.

Activity 2 The deployment of plant and labour. For this he will need:

Drawings showing the extent of each trade's involvement.

A 'construction manual' describing, by means of annotated drawings, the way in which each trade is to operate and which is explicit enough to ensure that no local querying or decision-making will be necessary.

An objective and realistic description of the quality standards required and the methods to be employed.

Activity 3 The preparation of a programme and decision on a method of operation. For this he needs:

Drawings giving an overall picture of his commitment.

Comprehensive information about the constraints of site, access and programme. A summary of his contractual obligations.

The need for a unified system What we are looking for is a complete information system which will satisfy these different user requirements and which will be at the same time:

• reasonably simple and economical to produce

• simple to understand and to use at all levels

• flexible enough to embrace information produced by various offices—structural, M & E etc

• capable of application to both small and large projects

• appropriate for use in both small and large producing offices.

The importance of the two latter points tends to be underestimated. Given a standard method of procedure a common experience is gradually built up, not only among contractors, but among assistants moving from one project to another within the office, or indeed moving between different offices. Nothing is more disruptive for architect, estimator and contract manager alike than to have to switch constantly from one working method to another.

It was with this in mind that the Project Information Group (commonly known by its somewhat unfortunate acronym) was set up in 1979 to identify more precisely the reasons for the inadequacies in building information noted on page two.

In the course of time the Group became transmuted into the Co-ordinating Committee for Project Information (CCPI), upon which the main building professional and contracting organisations were represented. In 1987 it published a sequence of Co-ordinated Project Information (CPI) documents which represent what is to date the most comprehensive statement of intent regarding the achievement of.better production information.

Among other aspects it acknowledges the concept of drawings, specifications and bills of quantities together forming the complete information package, and despite the existence of ingenious alternative methods which have been devised for particular situations it is not the intention of this book to disturb that long-standing tripartite relationship.

Consideration will be given in a later chapter to what information sometimes given on drawings may be more appropriate to the specification; but other than that this book will concern itself solely with drawings, regarding these as the base documents in the information package which it is the role of the specification to amplify, the bills to quantify (1.3).

The structure of working drawings

Every set of working drawings consisting of more than one sheet is structured, for it represents a more or less conscious decision on the part of the draughtsman to put certain information on one sheet of paper, and certain other information on others. Even were the reason for doing so simply that there is insufficient space on a single sheet of paper, a selection has still to be made of what to put on each sheet, and a sensible basis for that division has to be determined.

Indeed, the simplest of single sheet applications to a local authority for approval under the Building Regulations for the erection of a garage is likely to contain a small scale plan showing the site in relation to the surrounding neighbourhood as well as a dimensioned plan of the building itself. This in effect acknowledges the existence of some informational hierarchy within which certain different aspects of instruction about the building may sensibly be given in different places and in different ways (1.4).

In the following pages we shall be not so much seeking to impose a method of doing this as seeking out the structure inherent in the whole concept of building information, and trying to reflect it in the form that the information package will take.

Let us start our search at the point where the ultimate end product of the entire communications exercise is to be found—the building site.

What, where and how?

The information that an operative needs to know about each element of the building he is called upon to construct may be classified into three distinct types:

1. He needs to know what it is that he has to install or erect. Whether it be window frame, brick or cubic metre of concrete, he needs to know certain information about its nature and physical dimensions.

2. He needs to know where it is to be placed. This demands pictorial and dimensional information regarding its relationship to the building as a whole.

3. He needs to know how it is to be placed or fixed in relation to its immediately neighbouring elements.

Clearly these three questions—what, where and how—are fundamental to the business of building communications, and demand a variety of replies in practice if they are to be answered satisfactorily and without ambiguity. It may be useful to reflect for a moment on the degree of depth and comprehensiveness that may be required of these answers.

If the designer has devised a precise solution to the building problem set him by his client, then the information to be conveyed to the builder must be of sufficient detail to enable the unique nature of that solution to be appreciated and converted into physical building terms by a variety of people, most of whom will be unfamiliar with the original problem, and unaware of the chain of thought processes which has given rise to its solution.

drawing specification

and, in the case of fine aggregates, Zones 1 to 3 only sh nie maximum size of coarse aggregate shall not be less th otherwise specified*

Aggregates shall comply with B.S. 882 and shall be fre elongated particles, dust, clay films and other adherent shall not contain clay lumps exceeding MS by weight and f shall not contain more than by weight of silt.

In addition to the above it is required that the aggre lot produce a drying shrinkage in any of the concrete use

Methods of storage must be such as to ensure freedom f Intermingling and segregation. In general, separate coar bills of quantities

Foundation in trench, over 300 mm thick.

Extra over for placing around live drain.

Ditto, in pit, over 300 mm thick

Casing to steel beam, over 0.05 and not exceeding 0.10 nr sectional area,

Was this article helpful?

0 0

Post a comment