Flame-resistant shield for protected membrane roofs

1 . An inverted roof membrane assembly comprising:

a) a waterproofing membrane suitable for direct or indirect mounting on top of a roof decking,

b) at least one layer of the polymer foam insulation board directly or indirectly on top of a),

c) a flame-resistant fabric shield directly or indirectly on top of b), said flame-resistant fabric shield having a water vapor permeability of 1.0 perm or greater; and

d) a ballast layer directly or indirectly on top of c);

wherein the flame-resistant fabric shield comprises a nonwoven felt of staple fibers, wherein the nonwoven felt is a needle punched felt,

the felt having:

a water vapor permeability of 1.0 perm or greater,

a basis weight of about 150 to 800 grams per square meter, and

a thickness of about 1.5 to 6.0 mm;

wherein:

i) 20 to 100 weight percent of the total amount of staple fibers are re-purposed meta-aramid staple fibers; and

ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having a uniform cut length.

2 . The inverted roof membrane assembly of claim 1 wherein the felt has a basis weight of about 150 to 400 grams per square meter and a thickness of about 1.5 to 4.0 mm.

3 . The inverted roof membrane assembly of claim 1 wherein the felt further comprises up to 80 weight percent staple fiber having a limiting oxygen index of 24 or higher.

4 . The inverted roof membrane assembly of claim 1 , wherein at least 40 weight percent of the total amount of the staple fibers of the flame-resistant fabric shield are crimped staple fibers.

5 . The inverted roof membrane assembly of claim 1 wherein the flame-resistant fabric shield comprises:

i) 40 to 80 weight percent re-purposed meta-aramid staple fibers; and

ii) 20 to 60 weight percent crimped virgin meta-aramid staple fibers having a uniform cut length.

6 . The inverted roof membrane assembly of claim 1 , wherein the polymer foam insulation board has a foam density of at most 56 kg/m 3 (3.5 pounds per cubic foot), a thickness of at least 0.6 cm (0.25 inches), an RSI-value of at least 0.53 K·m 2 /W per 25.4 mm of thickness (R-value of 3.0 F°·ft 2 , h/BTU/inch of thickness).

7 . The inverted roof membrane assembly of claim 6 , wherein the foamed polymer foam insulation board has a foam density of 21 to 56 kg/m 3 and a thickness of 7.62 to 15.24 cm.

8 . The inverted roof membrane assembly of claim 1 , wherein b) comprises at least two layers of the polymer foam insulation board directly or indirectly on top of layer a).

9 . The inverted roof membrane assembly of claim 1 wherein the ballast comprises gravel, stone, soil, one or more pavers, a green roof structure or component thereof, or a blue roof structure or component thereof.

10 . A flame-resistant fabric shield comprising a nonwoven felt of staple fibers, the nonwoven felt having

a water vapor permeability of 1.0 perm or greater,

a basis weight of about 150 to 800 grams per square meter, and

a thickness of about 1.5 to 6.0 mm;

wherein:

i) 20 to 100 weight percent of the staple fibers are re-purposed meta-aramid staple fibers; and

ii) 0 to 80 weight percent of the staple fibers are crimped virgin meta-aramid staple fibers having a uniform cut length.

11 . The flame-resistant fabric shield of claim 10 wherein the felt has a basis weight of about 150 to 400 grams per square meter and a thickness of about 1.5 to 4.0 mm.

12 . The flame-resistant fabric shield of claim 10 , wherein the nonwoven felt is a needle punched felt.

13 . The flame-resistant fabric shield of claim 10 wherein the felt further comprises up to 80 weight percent staple fiber having a limiting oxygen index of 24 or higher.

14 . The flame-resistant fabric shield of claim 10 , wherein at least 40 weight percent of the staple fibers of the flame-resistant fabric shield are crimped staple fibers.

15 . The flame-resistant fabric shield of claim 10 , wherein

i) 40 to 80 weight percent of the staple fibers are re-purposed meta-aramid staple fibers; and

ii) 20 to 60 weight percent of the staple fibers are crimped virgin meta-aramid staple fibers having a uniform cut length.