How Heavy a Carpet Has to Be

How to read this sheet

Divide before you argue. The density column is the pile weight over the pile height and it is the only figure in a carpet specification the wear test responds to; the weight on its own responds to nothing. A range quoted in grams per square metre is being sold on the expensive half of a ratio, and the cheap half is sitting in the same specification being ignored. Work out the density of a construction you know passes, and you have the requirement for everything else you make in that class. What the answer turns on, and it is not arithmetic. The shortest pile the look allows is a judgement about a customer, not a calculation, and the sheet will not make it for you. Enter the height you already run and it will correctly report that there is nothing to save - which is the right answer for a specification that genuinely cannot move, and there are plenty of those. Enter a height you cannot defend and the saving is imaginary. The honest use is to enter what you would be willing to submit for approval, and then to submit it. The column that is not a saving. A quality built below the density its own class requires will pass the test it is submitted for, because that test is run on a new sample, and will fail on the floor eighteen months later in a building nobody associates with the mill. It is reported apart from the savings because it is money that has to be spent rather than money that can be kept, and a sheet that netted the two would be hiding a liability inside an opportunity. What is not modelled. Density is treated as the whole of the wear class, where in truth fibre type, twist, heat-setting and the backing all matter and a badly heat-set carpet at the right density will still fail. Appearance retention, which is what a customer actually complains about, is not the same as wear and is not here. Tuft density and gauge are absent, so a construction that meets the density with too few, too fat tufts will grin at the backing and this sheet will call it fine. And nothing here says whether the class is the right one to be selling against, which is a commercial question and usually the larger one.