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Measurements
The Securagard™ fragment retaining mesh curtain is designed to work by it being loosely installed allowing for the mesh to elongate and "unwind" as the projectiles impact with it. If enough velocity and weight is available the projectile will become encapsulated within the mesh. The height of the mesh should be the rough opening of the window area minus 1.5" for each rail to be installed. This allows for the installation of the S-clips, safety pin and T-bar glides. The width of mesh should be the rough opening dimension plus 50% for low level blast threats (0-4 P.S.I. positive over pressure), and plus 100% for high level blast threats (>4 P.S.I. positive over pressure), which will provide for a full box pleated look.
The rail system should be cut to fit tightly from left to right along both the head, sill or base of the opening. This ensures that once the safety pins are installed, the mesh will rest snugly alongside the vertical jambs of the opening.
The higher the explosive blast threat, the more it becomes necessary to have a tighter weave. The aluminum should only be utilized for low level blast threats. The tighter the weave the more efficient the mesh is against very small projectiles. The carbon steel works well for the low and higher explosive blast threats, once again choosing a tighter weave for the higher threats. The stainless steel would be better selected for the higher threats and/or for areas where corrosion resistance is required, once again choosing a tighter weave for the higher threats.
INSTALLATION
The Securagard™ rail system is installed in two different configurations depending upon the explosive blast threat severity. Low level blast threats (0-4 P.S.I. positive over pressure), can have the rail system installed at the head of the window opening, and left to hang in a draped fashion as long as at least 30% of the total drape height is below the window sill. If the window opening goes down completely to the floor then two rails will be necessary, one at the head and one on the floor. High level blast threats (>4 P.S.I. positive over pressure), must have two rails installed, one at the head of the opening and one at the sill or base of the opening.
Anchoring is accomplished with two rows of staggered anchoring the entire rail length with no less than every 8" on center spacing for low level detonations to every 6" on center spacing for high level detonations. Screw or bolt anchors are acceptable, however, the lengths should be long enough to go through the rail and casing material, and solidly provide for a minimum 1.5" anchoring into the structures frame work. The minimum anchor diameter should never be less than a number 10 in steel, with a minimum shear resistance of 1,450 P.S.I., and a minimum pullout resistance of 1,600 P.S.I. Always install the two anchors 1" from each end, then stagger front and rear anchors.

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