Identifying concrete blocks (CMU)

[phloaw]

Hello, this is a house in UK, built in the early '70s.
Some parts of the outer walls are made of concrete blocks.
I suppose they are one of the usual types: e.g., aggregate, lightweight or aircrete, but I'm not sure which one.
I would like to know in order to buy the appropriate anchors/fixings.
Any suggestion/input welcome.
Their size is approximately 44.5x22cm, they have no identifying signs or marks visible.
I attach pics.
TIA

Edited December 12, 2021 by phloaw
clarify

[saveasteading]

Blocks are standard sizes. What kind of fixing are you considering and for what purpose?

[phloaw]

3 minutes ago, saveasteading said:

Blocks are standard sizes. What kind of fixing are you considering and for what purpose?

Thanks. I need to hang a radiator on a dot and dab wall in the same house, and the blocks are the ones showed here. Need to decide what fixings.

[saveasteading]

There are  good fixings that will hold to the plasterboard, or you can use long screws to the block. I would trust the plasterboard, just use plenty of fixings in case someone sits on the radiator.

There are all sorts of fancy fixings but I would just use plastic wall-plugs, and plenty of them as the brackets have several holes. BUT pay the little bit more for a known branded make.

[phloaw]

4 hours ago, saveasteading said:

There are  good fixings that will hold to the plasterboard, or you can use long screws to the block. I would trust the plasterboard, just use plenty of fixings in case someone sits on the radiator.

There are all sorts of fancy fixings but I would just use plastic wall-plugs, and plenty of them as the brackets have several holes. BUT pay the little bit more for a known branded make.

 

Thanks. I'd still like to know whether those blocks are standard breeze blocks (aka aggregate) or aircrete (aka thermalite). Any guess?

[saveasteading]

Standard concrete by the looks of them. Easy to check with a chisel or drill, as concrete is very hard and thermalite etc is made from a paste, looks like grey aero underneath and turns to dust under a hammer or chisel.