Instrument devices shall be furnished with tag number. Common material for tag attached to the instrument is 316 SS. For instrument which is mounted on instrument stand, the mounting stand should be furnished with tag number from traffolyte (a brand name).
The attachment of traffolyte tag number on the instrument mounting stand is to avoid a problem which is usually encountered during maintenance so that when instrument device is dismantled, personnel is able to identify the mounting stand which belong to particular of instrument being serviced.
Instrument attached to panel, both for indoor and outdoor, is also usually tagged with traffolyte at the bottom of instrument location.
Traffolyte is a multi-layered phenolic which comprises of various color e.g black and white. To create a number, the upper layer is engraved so that there is color difference between bottom and upper layer hence form a readable text.
The most common color combination in black letter and white foreground which means the bottom layer color is black while the upper layer color is white. The white phenolic is engraved hence the black layered is visible as a text color.
Note that the same combination of black and white while reversing the position of layer (white letter with black background) shall be avoided as this arrangement would create future issue: dust or sand may be accumulated on the letter engraved hence cover the white color. Later the text will not clearly visible if to much build up dust or sand.