Re: Re: Tyvek ground cloth

On Sun, Jun 9, 2013 at 5:50 AM, jrwooden <jim-TZ6VOGY/[email protected]> wrote:

> **
>
> ... according to the Tyvek website the 1422A has a hydrostatic head
> rating, while 1422R & 1433R have no specification so ... likely they would
> not be as waterproof?
>
> Good point - properties chart for the various grades of Tyvek is found at

From
http://www2.dupont.com/Tyvek/en_US/products/tyvek_styles/tyvek_styles.html

[image: Inline image 1]

And

"Spunbonded Olefin with neither corona treatment nor antistatic agent
(e.g., Style 1073B) has a hydrostatic head in excess of 50 in. (127 cm). If
antistat is applied, the hydrostatic head will drop to 40-50 in. (102-127
cm). Corona treated and antistated Spunbonded Olefin (e.g., Style 1073D)
has a hydrostatic head that is less than 15 in. (38 cm)."

http://www2.dupont.com/Tyvek/en_US/products/product_properties.html#moisture

1422R (kite tyvek) has both antistatic and corona treatment (per above
chart) so hydrostatic head drops from 50 (building wrap tyvek) or less than
15 (kite tyvek - 1422R). Maybe 1422A which eliminates the corona treatment
has the best combination of properties with hydrostatic head of 40 inches.
Corona treatment (present in 1422R but not 1422A) seems mostly designed to
allow printing.