Sound proofing a boiler cupboard - safe and sensible?

[Cellophaneskies]

I have a modern Baxi combi boiler in my hallway. When it fires up, it is loud. It has a cupboard built around it with a floor to ceiling door, and the frame/side panel made from MDF. this dulls the noise a little but not as much as I’d like.

Between the side of the boiler and then MDF side panel I have about 10cm. I’m thinking about getting a rockwool slab of 5cm and putting it up on the inside of this panel. I’ll cover it with a thin hardboard or something to hide it.

My question is, is this safe or sensible. Boiler is already enclosed of course, and the product says it’s fire retardent (or similar wording). It won’t be pressing against the boiler, with still 5cm of space remaining.

I was going to stick some sort of MLV to the doors.

Does this sound wise or a fools endeavour..

 

[Wayners]

Rockwall slab will do nothing to stop noise.

Sound-insulating rubber insulation might be a better option although I've never used.
It's got a fire rating.

Soundblock board on resilient bars I have used which you put on ceiling and walls

 

[StephenStephen]

Can you access to cover the insulation on the inside with plasterboard? - that would make a difference

 

[Cellophaneskies]

Rockwall slab will do nothing to stop noise.

Sound-insulating rubber insulation might be a better option although I've never used.
It's got a fire rating.

Soundblock board on resilient bars I have used which you put on ceiling and walls

To confirm, it’s sound insulation slab, not just normal insulation!

Rockwool Sound Insulation Slab - 50 x 400 x 1200mm Non Combustible​

 

[Wayners]

Yeah.

I've used it. Just a thick bit of solid glass fiber.
I used behind resilient bars and 2 layers on sound block board here
On it's own it won't do anything