Language within some commercial intumescent coating specifications suggest that harder coatings are better.

That isn't true-read why here.

Truth aside, where one sits in the contract chain is a good indicator of how impactful they feel material hardness is to overall project success.

The owner/architect viewpoint

These stakeholders view a harder material as tougher and more durable, a sign that it will hold up for the lifetime of a building.

What they're missing: Hardness is neither the best nor the only way to judge fitness for purpose. They risk closing the door on intumescent technologies not formulated for high hardness.

The contractor viewpoint

One view is that hardness is almost meaningless. When a spec says a material needs to meet or exceed a certain hardness, you follow it.

Another is that hardness helps compare damage resistance. If contractors have a say in product specification, it's in their interest to choose one they won't have to go back and repair later.

What they're missing: Hardness is not the only way to assess damage resistance. In certain conditions, more pliable or flexible materials are more damage-resistant while harder ones are at higher risk.

The subject of intumescent material hardness is covered in depth in this article and this podcast episode.