These are visual warning labels furnished on all aluminum and fiberglass ladders since January, 1984.
These labels are heat sensitive material that turn black if any heat is ever present that is greater than approximately 300 degrees F. The 300 degree F temperature is used because once aluminum fire ladder materials (6061-T6 alloy) reach this 300 degree F (even if only for a moment), the ladder material may have lost at least 25% of it's load capacity. This heat exposure effect is not reversible in the ladder and can continue to accumulate over its entire lifetime.
NOTE: If any heat sensor label becomes black - remove the ladder from service at once and have the ladder load tested before the ladder is ever used again. If the ladder passes the load test - you have had a false alarm - replace the heat sensors and return the ladder to service. Replacement heat sensor labels are only available for ladders that have passed the load test. If the ladder does not pass the test, we will not supply you with new labels. Call the factory for details.
REMEMBER: Heat sensor labels that look OK do not make the ladder safe to use.
NFPA now requires 4 heat sensors and one instruction label per ladder section. Each heat sensor has an expiration date printed on them. If you have noticed any expired labels, conduct/schedule testing first per NFPA-1932 (Current Edition) and the expired labels must be replaced. New heat sensors are dated out for 5 years. Place 2 heat sensor labels below the 2nd rung from the top of each inside rail section (1 on the right inside rail - 1 on the left inside rail). Place the other 2 heat sensor labels, including one instruction label at the approximate middle point of each inside rail section (1 on the right inside rail - 1 on the left inside rail with instruction label)