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Table 6 WHO hole size guidelines and hole index used to assess physical integrity of LLINs

From: Textile testing to assess the resistance to damage of long-lasting insecticidal nets for malaria control and prevention

WHO 2013 guidelines Size banding Hole diameter Hole radius Area of hole Hole Indexa
cm d; cm r = d/2; cm r2; cm2 cm2
Size 1
Smaller than a thumb
0.5–2 1.25 0.625 0.3906 1.23 1
Size 2
Larger than a thumb but smaller than a fist
2.5–10 6 3 9 28.28 23
Size 3
Larger than a fist but smaller than a head
11–25 17.5 8.75 76.5625 240.56 196
Size 4
Larger than a head
 ≥ 26 30b 15 225 706.95 576
  1. A -area of the hole pr2; p = 3.142; a Area divided by 1.23; b Assumed diameter