Glossary - O

one-way latch action (np)
latch action in which the follower will turn one way only

open shackle padlock (n)
padlock in which a complete 180° hoop of shackle is exposed

opening cycle (np)
(Product specific term - see prEN 12650)

opening face (np)
side of leaf which faces the opening direction

opening force (np)
force required to move a leaf in the opening direction

opening light (np)
light which can be opened

opening moment (np)
torque generated at the door leaf by the user when opening the door (see also EN 1154)

operating cycle (np)
(see "test cycle")

operating element (np)
(Product specific term - see EN 179 & prEN 13637)

opposing closing edge (np)
(Product specific term - see prEN 12650)

out door
(Product specific term - see prEN 12650)

outer forend (np)
(see "faceplate")

outer stile (np)
(Product specific term - see prEN 12650)

outside (n)
side (of door, window etc) that faces towards the exterior of the building, or away from a protected area within the building (see also EN 179 & EN 1125)

outside access device (OAD) (np)
mechanism for opening an exit device from outside (see also EN 179 & EN 1125)

oval cylinder (np)
profile cylinder for which the cross-section of the housing is oval

overhead concealed door closer, door mounted (np)
overhead door closer mounted within the thickness of the door (see also EN 1154)

overhead concealed door closer, transom mtd. (np)
overhead door closer mounted within the thickness of the transom (see also EN 1154)

overhead door closer (np)
door closer positioned at or near top of door leaf

overhead door closer, surface mounted (np)
door closer positioned at or near top of door leaf, on the face of the door or lintel (see also EN 1154)

overload valve (np)
valve to reduce pressure extremes generated as a result of manual interference