46 CFR §58.16-35

1. (a)The outside of the cylinder enclosure housing liquefied petroleum gas cylinders, valves and regulators must be marked as follows:
2. (b)A durable and permanently legible instruction sign covering safe operation and maintenance of the gas-consuming appliance shall be installed adjacent to the appliance.
3. (c)“Operating Instructions” as listed in § 58.16-30 shall be framed under glass, or other equivalent, clear, transparent material, in plainly visible locations on the outside of the metal enclosure and near the most frequently used gas-consuming appliance, so they may be easily read.