Quote:

Originally Posted by

**KeeZ22**
... if any of you guys can explain and compare my data from those 2 pics i uploaded to like 703 and 705...

Looks like we're neighbours

(I'm from Romania)

First of all, hello everyone. I'm new here. Really helpful forum.

As it has been stated above, gas flow resistivity is the most important factor when it comes to sound absorption.

The densities are for those products are:

ROCKWOOL STEPROCK - C **120 KG/M3** meant for floor insulation - reduces impact noise (footsteps, etc.)

According to the graphs below, air flow resistivity should be 70.000 MKS Rayls/m = 70.000 KPa.s/m2

**roughly equivalent to OC 705 96 kg/m3** glass wool.

ROCKWOOL MULTIROCK - C **28 KG/M3** meant for general thermal insulation

According to the graphs below, air flow resistivity should be 8.000 MKS Rayls/m = 8.000 KPa.s/m2 roughly equivalent to a lower-density OC 701 - should be 18 kg/m3.

Owens Corning 700 Series specific density and air flow resistance. Density is taken from data sheets. I copied the Air flow resistance from one of Avare's posts dating back to 2008, when he mailed Owens Corning asking for the information. So It's not published official information (from what I gather, NASA measured the 703 to be 24.000 MKS Rayls/m)

OC 701 1.5 pcf = 24 kg/m3 = 8.000 MKS Rayls/m = 8.000 K Pa.s/m2

OC 703 3.0 pcf = 48 kg/m3 = 16.000 MKS Rayls/m = 16.000 K Pa.s/m2

OC 705 6.0 pcf = 96 kg/m3 = 30.000 MKS Rayls/m = 30.000 K Pa.s/m2

OC 707 7.0 pcf = 112 kg/m3

As a general rule of the thumb, in East Europe, Rockwool has the following system for describing density:

**ROCKWOOL AIRROCK LD LOW DENSITY - 40 kg/m3 - roughly equivalent to OC 701 or 711**

ROCKWOOL AIRROCK ND NORMAL DENSITY- 50 kg/m3 - roughly equivalent to OC 702

ROCKWOOL AIRROCK HD HIGH DENSITY - 70 kg/m3 - roughly equivalent to OC 703

ROCKWOOL AIRROCK XD EXTREME DENSITY- 90 kg/m3 - roughly equivalent to OC 704
All of these equivalents are based on the two graphs below. Please correct me if I'm wrong.

The examples above are referring to a "general building" product, but I suspect it's mostly the same as the better-known Rockwool RW series, measured in

Bob Gold's Absorption Coefficients Table
Rockwool RWA45 = 45 kg/m3

Rockwool RW3 = 60 kg/m3

Rockwool RW5 = 100 kg/m3

Rockwool RW6 = 140 kg/m3

Quoting

Scott R. Foster:

"...rockwool requires a higher density because of the nature of the material. Generally you could expect similar acoustic performance with a panel about 50% denser in grade [this would approximately match the gas flow properties of 703] which works out to about 5 lbs. per cubic foot or about 60 kg/m3. But even at this density rockwool has inferior handling properties to 703 and yields a heavier panel [no biggy for a hang forget application, but if portability matters this is a flaw]."

Quoting

Andre Vare:

"Rockwool is broady equivalent at slightly denser at around 48 kg/m^3 fiberglas at 64 kg/m^3. the relationship acoustically is not linear."

Some useful graphs - I thing I saw them posted somewhere on the forum before, sorry for the redundancy but I believe they're important:

Source:

Rockwool Marine & Offshore Acoustic Manual - Highly recommended reading

Source:

Building Acoustics, author Tor Erik Vigran