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1.3 Drawings, specification and bills of quantities. Each has a clearly defined role in the information package

So if we are dealing with a window the single question—What window?—may proliferate into a large and varied series: what are its overall dimensions; what does it look like; what material is it made from; what is its glass thickness; what furniture does it have; what are its finishes? These and many other questions will arise from consideration of the nature of a single component.

Similarly we need to know where in the building it is to be installed, implying the need for dimensional information in three planes; and how it is to be installed—how it sits in relation to the lintol above it, how it relates to the vertical DPCs in the adjacent wall cavities, how many fixing points are required and what is the nature of their fixing. And so on.

The amount of information required so that the description of any aspect of the building will be unambiguous must always be a matter for intelligent consideration. The strength and density of bricks forming footings below ground level, for instance, will be fit subjects for precise description, whereas their colour will not.

But two fundamental principles emerge which will be found to hold good at all times.

1. All building information may be classified into three basic categories, depending upon which of the three basic questions—how, where and what—it purports to answer.

2. All building information is hierarchic in its nature and proceeds from the general to the particular.

This latter observation requires some discussion, because the sequence in which the three questions emerge which were posed at the start of this section may suggest that the seeker after information starts with the component and its nature, and then works outwards to a consideration of where and how to install it. This sequence is in fact occasionally true—the window manufacturer, for example, would tend to consider the type of windows he was being called upon to make before determining how many of them there were in the building, and how they were distributed throughout it.

But in general terms the reverse is true. Almost every user of the information package will wish to know that there is a wall of finite dimensions with windows in it which forms the outer boundary of the building, before seeking to determine the various forms that the windows might take or the precise nature of the bricks and their pointing.

Since this is also the manner in which the designer will logically work, there is little difficulty, and every advantage, in devising a system in which the search for information starts with the question Where?, and in which the answer to this question provides within itself the indication as to where the answers may be found to the supplementary questions What? and How?

1.4 Detail from an early example of elementalisatioti. Drainage plan by James Adam, c. 1775 (RIBA Drawings Collection)

Primary structuring—by information type What has been outlined is a method of primary structuring of information according to its type and which may be summarised and named as follows:

• Location information, answering the questions: where are components to be built or installed, and where may further information about them be found?

• Component information, answering the question: what is the component like?

• Assembly information, answering the question: how are the various components to be related one to another—how are they to be assembled?

This type of structure, and the search pattern it generates, is illustrated in 1.5.

The schedule: Into this neatly classified system must now be introduced that somewhat hybrid creature, the schedule. And here again some fundamental questioning is needed to ensure that it will fulfil its proper function.

The idea of using written schedules, or lists of information, instead of drawings exists in most information systems and has its source in a variety of motives, not all of them necessarily valid. It is assumed that they are economical of drawing office time; that quantity surveyors, contractors and suppliers alike all welcome them; that they provide a ready check that the information conveyed is comprehensive.

These reasons do not always stand up to close examination. Schedules are only economical if they are simpler than the drawings they replace; the architect should not necessarily be doing other people's jobs for them; suppliers more often than not produce their own schedules because the architect's schedule is not in a form which they find usable, and some schedules attempt to provide so much information in so complicated a form that mistakes and omissions readily occur.

Nevertheless, they have a role to play, and used sensibly and with forethought they form an essential element in the information package.

Some principles affecting scheduling may be enumerated:

location

Their initial function is to identify and list components possessing common characteristics—eg windows, doors, manhole covers, etc.

They should not attempt to provide comprehensive information about the component; they should serve rather as an index to where the relevant information may be found.

They should initiate a simple search pattern for the retrieval of component, sub-component and assembly information.

They are only worth providing if the component in question has more than one variable. For instance, if you have windows of three different sizes which are identical in every other respect, then size is the only variable and you may as well write 'Window Type 1' on the Location Plan as 'Window No 1'. But if each window size may be fixed either into a brick wall or a pre-cast concrete panel then the assembly information required is a second variable.

Window Type 1 may be combined with jamb detail type 1 or type 2, and it is for this greater degree of complexity that it is preferable to prepare a schedule.

location

component assembly

1.5 The fundamental search pattern generated by the questions Where?, What? and How?

component assembly

1.5 The fundamental search pattern generated by the questions Where?, What? and How?

The great virtue of the schedule is that it can direct you to a vast amount of information about a given component in a way that would be impossible to achieve by any system of direct referencing from a location drawing. Consider a window—thirty-seventh, shall we say, of fifty on the second floor of a multi-storey block of offices. The method chosen for giving it a unique reference is unimportant for the moment—W2/37 is as good a piece of shorthand as any for the purpose—but it is obvious that this simple means of identification may be shown equally on a drawing or a schedule (1.6).

Thus, there are two ways of providing a catalogue of the windows on the job, in which W2/37 is seen to take its place between W2/36 and W2/38. But if we were now to add to the drawing a fuller description of what W2/37 in fact consists of, then we should meet an immediate difficulty—there just is not space to do it (1.7).

Consequently when it is considered that the information given only scratches the surface of what the recipient really needs to know, and that similar information will need to be provided about W2/1 to W2/50—to name but the windows on the second floor—it becomes

INi/36

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