Warning plates get value-engineered out of projects more often than any other item. Then a landscaping crew puts a bucket through a gas main two years later, and everyone asks why there was nothing in the trench.
A rigid PE plate with a laminated galvanised steel strip does two jobs: it is a physical barrier against backfill, and it is detectable from the surface with a pipe locator to about 1.2 m. Tape does the first job only, and only until it tears.
Print the language of the country it is going into. We have shipped plates printed in English, Arabic and Russian for the same project — the warning is worthless if the operator cannot read it.
