UV Transmittance

UV Transmittance Measurements

Treatment with U-V-Block Sun Protector fabric treatment by Atsko, Inc.

Tested by International UV Testing Laboratories, Aubrun, AL in accordance with test method AATCC183.

Fabric supplied by Test Fabrics, Inc. all white and lightweight with low initial UPF* using Labsphere Ultraviolet Transmittance Analyzer.

Fabric 437W Bleached Cotton "T" Shirt Fabric.
 
%UVA Transmitted
%UVB Transmitted
%UVA Blocked
%UVB Blocked
UPF*
Untreated
25.02
16.38
47.98
83.62
5.41
Treated
0.96
0.89
99.04
99.11
117
Treated Washed 6
1.58
1.26
98.48
98.74
80

 

Fabric 437W Bleached Cotton "T" Shirt Fabric.
 
%UVA Transmitted
%UVB Transmitted
%UVA Blocked
%UVB Blocked
UPF*
Untreated
25.02
16.38
47.98
83.62
5.41
Treated
0.96
0.89
99.04
99.11
117
Treated Washed 6
1.58
1.26
98.48
98.74
80

 

Fabric 459 Bleached Cotton Knit Sport-Shirt Fabric.
 
%UVA Transmitted
%UVB Transmitted
%UVA Blocked
%UVB Blocked
UPF*
Untreated
18.49
9.72
81.51
90.28
8.79
Treated
2.81
2.78
97.19
97.22
37
Treated Washed 6
2.38
2.03
97.62
97.97
49

Note: Shrinking and fuzzing decreased UV Transmittance with more washes.

Fabric 419 Bleached Mercerized
Combed Cotton Dress-Shirt Fabric.
 
%UVA Transmitted
%UVB Transmitted
%UVA Blocked
%UVB Blocked
UPF*
Untreated
29.59
20.51
70.41
79.49
4.4
Treated
0.98
0.88
99.02
99.12
116
Treated Washed 6
2.01
1.7
97.99
98.3
60

Note: Treatment applied twice because thin material absorbed little product.

*UPF is nominally a measure of how much longer you could stay in the sun just like SPF. In actual use UPF of 15 ~ SPF of 45 because most users get only about 1/3 the advertised protection. SPF is a measure of skin reddening caused by UVB measured under ideal conditions. UPF includes UVB (290-320 nm.) and also UVA (320-400 nm.), which causes damage and cancer with little or no reddening. UPF is measured by precise instruments and represents the minimum level of protection expected.

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