Capítulo 2: La Sociedad Argentina de los 90
2.1 El gobierno menemista
2.3.2 La vida puertas adentro
Inevitably there will be cases where more than one set of dimensions relates to a single description. These can be linked to the recorded dimensions with a bracket line (Figures 2.20
Figure 2.20
Figure 2.21
Waste calculations.
Bracket line and signposting.
Where two or more descriptions apply to a single set of dimensions, each description is separated by an ampersand. This process of ‘anding-on’ is fundamental to the group method of measurement and avoids the need to write down dimensions more than once. Care should be
taken to ensure that the same unit of measurement applies to each of the items linked together by an ampersand, as the total of all the quantities to the left of the bracket relates to each and
every description to the right of the bracket.
On occasion, it is convenient to use an ampersand to link two or more items that have different units of measurement. This is perhaps best demonstrated by Figure 2.23.
In this case, three different classes of work have been grouped together as they share a common set of base dimensions (in this instance it is the girth or perimeter length of a room). The first three items are measured in linear metres while the last two are measured as an area. Rather than starting a new set of dimensions, it is far simpler to introduce a conversion factor (in this case the constant floor-to-ceiling height). This must be made clear to the person carrying out the squaring and is usually shown by inserting a horizontal arrow across the dimension and squaring column into the description column where the conversion takes place (in this one instance a mathematical times symbol [×] can be used). A space for the resulting quantity must be left, and the appropriate unit of measurement should be identified after the space. This is a more advanced technique, which anyone new to recording dimensions is advised to avoid until such time as the basic principles of booking dimensions are clearly understood.
2.07 Spacing of dimensions and signposting
The spacing of dimensions and descriptions is an important part of the measurement process. Clear, well-spaced dimensions are easy to follow and can be readily checked by others. While there are no written rules about the presentation of measured items, Figure 2.24 provides an indication of the spacing and layout of a typical sheet of booked dimensions.Figure 2.22 Anding-on (the ampersand).
Every effort should be made in the take-off to ensure that dimensions and waste calculations can be traced back to the drawing. Signposts or location notes can be used in the description column to provide this cross-reference. These should appear on the right of the description column parallel with the dimension to which they relate. A simple line or ring around this location note prevents it being read as part of the description (Figure 2.21).
2.08 Abbreviations
The use of abbreviations when writing descriptions is commonly practised by measurers. Apart from the practical limitations of space, a great deal of time is saved by shortening the more frequently used words. A full list of the more commonly recognised abbreviations is given in Appendix I. Individual surveyors and practices tend to develop their own forms of abbreviation and, although there are no hard and fast rules, it is always important to bear in mind that others must be able to fully understand the written description. While abbreviations are acceptable in both the take-off and the abstract, their place in the completed BQ should be restricted to those listed in NRM2 1.6.1. Should there be the slightest chance that a word or term could be misinterpreted in the finished BQ, it must be written in full.
Many of the descriptions in a take-off are repeated several times often in the space of a few pages. Where this occurs time can be saved by referring to a previous similar or identical description. This is achieved by using the abbreviation abd. (as before described). See Figure
Figure 2.23
2.25.
Figure 2.24 Sample layout of dimension paper showing booked dimensions, descriptions,
Figure 2.25 Abbreviations and short written descriptions. The description in (a) appears on
the dimension sheet. Later in the take-off, more trench excavation is measured and the description might be written as (b) implying all the detail of the previous description. Later again more trench excavation is measured, but this time the maximum depth of dig exceeds 2.00 m but not 4.00 m and this is described in (c). Note: For the sake of clarity, dimensions are not shown. The word ‘ditto’ is often used in the same way, although in this instance it is understood to refer to the immediately previous description. For example, the following dimensions might be booked when measuring drainage work (Figure 2.26). The full description for the second example should read, ‘Drain runs, average trench depth 1000–2000 mm, 110 mm-diameter glazed clayware jointed with plastic couplings in the running length bedded and surrounded in pea gravel.’
Care should be taken when using either technique, since it is easy to misdirect the intended back-reference.
2.09 Adjustments
This is the term that measurers use to describe an alteration to a set of previously recorded dimensions. Generally this is necessary because it is easier and safer to over-measure an item in the first instance and make a deduction or adjustment later. Consider the measurement of a carpet for an office floor which is interrupted around its perimeter by the ‘footprint’ of a number of concrete columns. Rather than attempt to break this area down into a series of strips,
Figure 2.26
it is far simpler to over-measure initially and then deduct the area of flooring covered by the columns.
It is usually assumed that all booked items are additions and there is consequently no need to write the word add each time a description is recorded. The opposite of this is the case with respect to deductions, and it is vital that this is made clear to the squarer. A deduction will generally follow the item which gave rise to that adjustment (see previous example).
There are two methods generally recognised for making adjustments, and the difference is purely a matter of presentation. An example for each of these follows.
Care should be taken when making adjustments to a number of descriptions linked to the same quantity using an ampersand. This can become particularly confusing unless the word ‘deduct’ is included for every adjustment and not just the first (Figure 2.28).
As shown in Figure 2.29, even though the intention of the measurer is clear, once the first description is transferred to the abstract and lined through, the squarer has lost all reference to the instruction to deduct the remaining items and it is likely that these quantities will be added rather than omitted.
Short written descriptions and abbreviations. Note: For the sake of clarity dimensions are not shown.
Figure 2.27
Figure 2.28
Making adjustments.
Figure 2.29 Adjustments (deductions) sharing the same dimensions.
2.10 Location notes/signposting
An often overlooked, but nonetheless important, part of taking-off quantities is the presentation of dimensions and descriptions. As dimensions are booked it is useful to make a brief note to identify the source or location of the quantities. Should there be a need to check how a BQ item was established, the individual sets of dimensions can be traced back to the drawing. These notes are referred to as ‘signposts’ or ‘location notes’ and are recorded on the right-hand side of the description column parallel with the quantity to which they relate. To avoid these becoming confused with the description of the work being measured, they can be distinguished from the wording of the description with a semi-circle or ring around them (Figure 2.30).