Colour coding

For easy identification and prompt maintenance it is mandatory to segregate all control wires when they are carrying more than one control supply (e.g. at different voltages and both a.c. and d.c.), and run them in separate bunches. The control wires must also be of different colours for different control supplies. The colour codes have been standardized for different control supplies (refer to lEC 60445). 

Identification by labels, numbers, colour coding etc. of vessels, transfer lines and valves. 

Provide warning notices to identify containers and areas where corrosive chemicals are in use, and instructions regarding necessary protection, particularly eye protection areas Identify vessels, pumps and pipelines (e.g. colour coding, numbering)... 

Table 9.2 Specific colour codes for selected compressed gases...

All cylinders must be properly labelled and colour coded (BS 349). 

Cylinders that cannot be properly identified should not be used do not rely on colour code alone. 

AMD 2 Recommendations for colour coding to indicate the extinguishing media contained in portable fire extinguishers (AMD 9740) dated October 1997. With BS EN 3 Parts 1 to 6, supersedes BS 5423 1987... 

This should be consulted for the colour coding of gas mixtures used for inhalation e.g. medical and breathing apparatus mixtures containing oxygen. 

Safe operation is generally assisted by simplification of piping and valve arrangements, and by their identification, e.g. by colour coding or tags. Logical arrangement can also serve as a prompt in identification. 

Colorimetry, See Analytical techniques Combustion chemistry, 40 products, 41, 42, 502 spontaueous, 18, 41, 43, 214, 216 Communicatious, 427, 428 Compound specific analyzers, 311 Compressed gases colour coding, 271 construction materials, 266 first aid measures, 280 hazards, 265 precautions, 272, 403... 

Hetzel A, Eckenweber B, Trummer B, WemzM, Schumacher M, von Reutern G. Colour-coded duplex sonography of preocclusive carotid stenoses. Eur J Ultrasound 1998 8(3) 183-191. 

The NFPA code is represented in a diamond containing 4 sectors, respectively toxicity, inflammability, reactivity and special risks . A coloured code that will appear on glass labels, at the back of transport vehicles, room doors etc enables the danger to be better noted. It is used by American companies although some French companies have also adopted it and it appears to be an efficient device. 

Fig. 1 Comparison of the experimentally determined geometries of the hydrogen-bonded complex H3N-- -HC1 and its halogen-bonded analogue H3N- C1F (both drawn to scale) with a non-bonding electron-pair (n-pair) model of NH3. Here, and in other figures, the n-pair electron distribution is drawn in the exaggerated style favoured by chemists. The key to the colour coding of atoms used in this and similar figures is also displayed...

Fig. 2 The experimentally determined potential energy V(), expressed as a wavenumber for convenience, as a function of the angle in the hydrogen-bonded complex H20- HF. The definition of

Fig. 3 The potential energy V(

Fig. 4 The experimentally determined geometries of H2S- -HC1 and H2S- -C1F drawn to scale. The n-pair model of H2S, as discussed in the text, is shown for comparison. See Fig. 1 for key to the colour coding of atoms...

Fig. 8 The n-pair models of 2,5-dihydrofuran, oxetane and oxirane (first column) and the experimental geometries of their complexes with HC1 (second column) and C1F (third column), each drawn to scale. The angle 0 is almost identical in B- HC1 and B- ClF for a given B but increases from 2,5-dihydrofuran, through oxetane, to oxirane, as expected from the model (see text). The non-linearity of the hydrogen bond increases monotoni-cally from 2,5-dihydrofuran to oxirane. See Fig. 1 for key to the colour coding of atoms...

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