STRENGTH AND DURABILITY
Various documents, including BS 8214, stress the importance of specifying the appropriate classification of doors to ensure long-term performance under anticipated uses. These classifications are best derived from tests described in BS DD 171 : 1987, ‘Guide to specifying performance requirements for hinged or pivoted doors (including test methods)’, although equivalent European standards are now available.
The following classifications apply:
LD light duty – low frequency of use by those with a high incentive to exercise care, e.g. private house owners.
MD medium duty – medium frequency of use primarily by those with some incentive to exercise care, although with some chance of accidents or misuse.
HD heavy duty – high frequency of use by the public and others with little incentive to exercise care where accidents or misuse could occur.
SD severe duty – subject to frequent violent usage.
GE Door Manufacturing doorsets are generally SD rated, however some high acoustic, and special performance doors will be HD.
The DD171 Test
To perform satisfactorily in each category, a door assembly must attain specific levels of performance. These include:
Strength – slamming, impact, torsion, deformation, closure against obstruction, resistance to jarring, abusive forces on door handle.
Operation – ease of opening and closing.
Dimensional requirements – stability, no bowing or twisting.