Page 172 - CW E-Magazine (20-5-2025)

Special Report

Thermal resistance of insulation insulation used in modern times. Because make it fire resistant. However, it is a
material is expressed by “R” Factor, of how it is made, by effectively weav- non-combustible material, so can pre-
which is a measure of the resistance to ing fine strands of glass into an insula- vent the spread of fires up to 1,400°F,
heat flow. R factor can be determined tion material, fiberglass is able to mini- but may not always be the best option
for a single insulation material for mize heat transfer. The main downside when extreme heat is present. Mine-
a specific thickness, by dividing the of fiberglass is the danger of handling ral wool has an R-value ranging from
thickness of the insulation in inches by it. Since fiberglass is made out of finely R-2.8 to R-3.5. (Figure 2).
the K factor (thermal conductivity of woven silicon, glass powder and tiny
insulating material in watts per meter shards of glass are formed. These can
kelvin) according to the following cause damage to the eyes, lungs, and
expression: R factor = the thickness even skin if the proper safety equip-
divided by the K factor or R=t/K. ment isn’t worn. Nevertheless, when
the proper safety equipment is used,
Example: With rigid urethane foam fiberglass installation can be performed
insulation having thickness of 3 inches without incident.
and K factor of 0.15 watts/mK, the “R”
factor = 3/0.15 = 20. Fiberglass is an excellent non-
flammable insulation material, with Fig. 2: A typical Mineral Wool Insulating
The insulation material for a specific R-values ranging from R-2.9 to R-3.8 Material
application is selected basically by per inch. If you are seeking a cheap Cellulose
considering the R factor. However, the insulation this is definitely the way to Cellulose insulation is perhaps one
overall economics (life-cycle cost), go, though installing it requires safety of the most eco-friendly forms of insu-
safety factor (flammability), and envi- precautions. Be sure to use eye protec- lation. Cellulose is made from recycled
ronmental factor (eco-friendly) aspects tion, masks, and gloves when handling cardboard, paper, and other similar mate-
also must be considered. However, this product (Figure 1). rials and comes in loose form. Cellu-
important characteristics with parti- lose has an R-value between R-3.1 and
cular standards in relation to CUI can R-3.7. Some recent studies on cellulose
be listed below(1, 2): have shown that it might be an excel-
Water absorption (ASTM C610 or lent product for use in minimizing fire
ASTM C612) damage. Because of the compactness
Leachable chlorides content (ASTM of the material, cellulose contains next
C871 or ASTM C795) to no oxygen within it. Without oxygen
Hydrophobic behaviour within the material, this helps to mini-
Compressive strength (when foot mize the amount of damage that a fire
traffic can be expected) Fig. 1: Fiberglass Insulation Material can cause.
Dimensional stability, etc.
Mineral wool So not only is cellulose perhaps one
common insulation materials Mineral wool actually refers to of the most eco-friendly forms of insu-
There are plenty of cheap and com- several different types of insulation. lation, but it is also one of the most fire-
mon insulation materials available on First, it may refer to glass wool which
the market today. Many of these have is fiberglass manufactured from recyc-
been around for quite some time. Each led glass. Second, it may refer to rock
of these insulation materials has their wool which is a type of insulation made
own ups and downs. As a result, when from basalt. Finally, it may refer to slag
deciding which insulation material you wool which is produced from the slag
should use, you should be sure to be from steel mills. The majority of mineral
aware of which material would work wool in the US is actually slag wool.
the best in any situation.
Mineral wool can be purchased in
Fiberglass insulation batts or as a loose material. Most mine- Fig. 3: A typical picture of cellulose insulation
Fiberglass is the most common ral wool does not have additives to material

172 Chemical Weekly May 20, 2025

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