So what does a British Standard document look like?

All Standards need to be clear and unambiguous in the way they are presented. Those that deal with different kinds of method (for example methods of analysis or methods of evaluating performance) are not all the same, but look similar. Many of the standards for testing properties of materials have eight or more headings. Let's look at some of these headings in more detail:

1. Scope
   This tells you what the test procedure can be used for. For example, BS EN ISO 10545-5:1998 (a British Standard for testing the impact resistance of ceramic tiles) says:
   "This part of BS EN ISO 10545 specifies a test method for determining the impact resistance of ceramic tiles by measuring the coefficient of restitution".
   Note: BS EN ISO 10545 is a European and international standard that has been adopted as a British Standard.
2. Principle
   This tells you the scientific principle on which the standard is based. BS EN 1936:1999 (a British Standard for testing the density of natural stone) says:
   "After drying to constant mass, the apparent density and the open porosity are determined by vacuum assisted water absorption and submerged weighing of specimens. The real density and the total porosity require the specimen to be pulverized". You'll notice quite a few technical terms (what's "apparent density"? for example). That's why British Standards also have a section called definitions.
   Note: BS EN 1936 is a European standard that has been adopted as a British Standard.
3. Definitions
   This describes much of the terminology used throughout the test, to avoid ambiguity. For example, in the Principle above, the term "apparent density" is used. This is defined as:
   "Apparent density (rb) the ratio between the mass of the dry specimen and its apparent volume"
   And yes, you've guessed it, there's also a definition given for "apparent volume"!
4. Symbols
   This tells you the exact meaning of any symbols used, for example:< br/> "(rb) the real density of the specimen, in kilograms per cubic metre"
5. Apparatus
   This tells you all the equipment you'll need to carry out the test.
6. Test Specimens
   In some tests, the test specimen (in other words, the object you are testing) has to be a certain size or shape. It may also have to be prepared in some way. This section also tells you how many specimens you should test (slight variations and differences can happen in the testing of more than one specimen, so we should repeat experiments to be sure of our results). If we look at BS EN ISO 10545-5:1998, we see an example of this:
   "A minimum of five test pieces in dimensions 75 mm x 75 mm cut from five tiles. Tiles with fixed dimensions less than 75 mm may be used".
7. Test Procedure
   Believe it or not, this tells you the procedure you must follow; it tells you what you have to do. Sometimes there are diagrams to help you.
8. Expression of Results
   This section tells you how you should write your results, and gives you the formulae for any calculations you have to carry out. It also tells you what units should be used. For example, in BS 2782-3 (a British Standard for testing impact resistance of plastic), the following equation is given:
   S = (v0 - p/3m) x t
   where,
   m is the falling mass, in kilograms
   v0 is the impact velocity just before impact, in metres per second
   t is the time to peak force or the time to failure, in seconds
   p is the impulse imparted up to the time of occurrence of the peak force or up to the time of failure, in Newton seconds
   This section tells you how you should write your results, and gives you the formulae for any calculations you have to carry out. It also tells you what units should be used. For example, in BS 2782-3 (a British Standard for testing impact resistance of plastic), the following equation is given:
   S = (v0 - p/3m) x t
   where,
   m is the falling mass, in kilograms
   v0 is the impact velocity just before impact, in metres per second
   t is the time to peak force or the time to failure, in seconds
   p is the impulse imparted up to the time of occurrence of the peak force or up to the time of failure, in Newton seconds
9. Test Report
   This final part outlines what you have to write in your report. BS EN ISO 10545-5:1998, for example, says:
   The test report shall include the following information:
   
   • a reference to this part of BS EN ISO 10545;
   • a description of the tiles;
   • the coefficient of restitution of each of the five test specimens tiles;
   • the average coefficient of restitution;
   • any indentation or cracking of test specimens.