Chevrons (red/yellow) are required to be NFPA compliant. If the truck does not have them installed or are different colors when built then most manufacturers will make the department sign a waiver stating that the apparatus does not meet NFPA requirements.
We are going through a similar situation right now, previous engine built by Manufacturer A in 2014 has the red & yellow chevron to meet NFPA, actual color of the yellow scotchlite is "Lemon Yellow". No issues.
Currently having a ladder built by Manufacturer B, they want us to sign a waiver because "Lemon Yellow" in not yellow per the NFPA list. Last I checked yellow was yellow but they are taking a literal translation that "yellow" scotchlite (looks more orange) is the only yellow allowed because NFPA just says yellow (not lemon yellow). We pulled the data sheet and Lemon Yellow actually out performs the regular Yellow. We will see what happens with this as we are pushing back on it.
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