Technical terms simply explained.

The athmer glossary contains the most common terms relating to automatic drop seals and finger protection systems.  

athmer glossary

Actuation

The motion a drop seal makes when it’s sealing profile drops to the floor.

Actuator

Drop seal component that protrudes from one or both sides of a door and is compressed by contact with the door frame. Upon compression it activates the inner rail and sealing profile, pushing them towards the floor.

Automatic drop seal

An item of door hardware located at the bottom of a door, typically made from aluminium with built-in spring mechanism. It contains a sealing profile gasket typically made from silicone, which drops automatically upon door closing to form a seal with the floor by sealing the gap at the bottom and retracts upon door opening.

Backset

An ironmongery term to describe the distance between the door edge and the specified part of a door hardware item, e.g. the centre of the bolt on a flush bolt or the centre of the spindle on a door lock.

Delayed drop

An athmer technology available with selected drop seals. It delays actuation of the seal for 6-8 seconds after the door closes. A delay in actuation will prevent pressure changes from affecting the door operation. This feature is particularly useful in positive-pressure environments, a growing application in hospitals and biosafety labs

Double actuation

An athmer technology available with selected drop seals. These models have an additional actuator on the latch side of the door, spreading actuation pressure more evenly over the door. This feature is particularly useful with wide doors and supports long-term durability.

Fire door

An engineered life safety device. Fire door is a term often used to describe a full fire door assembly including the door leaf, frame and essential hardware, which has been designed to resist fire for a specific period of time.

Graphite intumescent strip

A general term for intumescent made from intercalated graphite, one of the three main types of intumescent material. Common characteristics of graphite-based intumescent include an aggressive multidirectional expansion, production of a light, fluffy material and an initial activation temperature of around 200°C.

Head & jambs

The two types of component that together make up a door frame. The jambs are vertical members positioned at each side of a door opening. The head is a horizontal member positioned at the top of a door opening.

Inner rail

Drop seal component used to hold the sealing profile typically made from aluminium. It is contained within the main outer housing and drops to the floor during seal actuation.

Interdens®

A specific brand of phosphate-based intumescent material, a registered trademark of BASF Wolman GmbH, Sinzheim, Germany.

Intumescent seal

A seal that becomes active when subjected to elevated temperature and impedes the flow of heat, flame or gases. Upon activation it expands to fill gaps and voids in a fire resistant structure, for example a fire door assembly. Sometimes referred to as a fire seal.

Meeting stile

The gap where a pair of doors meet.

Overload protection

An athmer technology present in selected drop seals that automatically detects when the sealing profile has dropped far enough and cuts off further actuation pressure. Overload protection ensures a consistent, even seal and protects the seal’s components from excessive pressure.

Palusol®

A specific brand of silicate-based intumescent material, a registered trademark of BASF Wolman GmbH, Sinzheim, Germany.

Parallel actuation

An athmer technology incorporated in selected drop seals that drops the sealing profile evenly on both sides of the door. Parallel actuation prevents seal dragging and supports long-term durability.

Perimeter seal

A flexible seal used to seal the head & jambs of a door frame. Sometimes referred to as a frame seal. It can be rebated or fixed with self-adhesive tape.

Phosphate-based intumescent

A general term for intumescent made from mono ammonium phosphate, one of the three main types of intumescent material. Common characteristics of phosphate-based intumescent include an almost pressureless multidirectional expansion, production of a sticky meringue-like foam and an initial activation temperature of around 150°C.

Press plate

A thin metal plate often supplied with our drop seals, used to prevent damage to door frames. They are supplied as an accessory to our drop seals.

PVC (polyvinyl chloride)

A synthetic plastic polymer that can be extruded in both rigid and flexible forms for a variety of uses.

PVC-encased intumescent seal

A common type of intumescent seal that consists of an intumescent material covered by a protective PVC casing.

Self-extinguishing, flame-retardant silicone

A type of elastomer (rubber) containing silicone, which when set alight will extinguish flames by itself. Standards available to test the performance of this type of material include UL 94.

Silicate-based intumescent

A general term for intumescent made from hydrated sodium silicate, one of the three main types of intumescent material. Common characteristics of silicate-based intumescent include a uniaxial expansion, production of a solid foam and an initial activation temperature of around 110-120°C.

Sliding actuator

A particular type of actuator developed by athmer and made from a technical nylon material, designed to ‘slide’ across door frame surfaces. This type of actuator reduces friction with the door frame, protecting both the actuator and door frame from long-term wear.

TPE (thermoplastic elastomer)

A type of copolymer (usually a mix of plastic and rubber) that consists of materials with both thermoplastic and elastomeric properties.

Working temperature

The temperature range within which a seal will function correctly and as described. Sometimes referred to as operating temperature.

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