Hermetic Sliding Doors vs Automatic Sliding Doors

Sealed and standard automatic sliding doors look similar from a distance: a glass or solid leaf that slides aside when someone approaches. The difference is what happens when the door closes. A standard automatic sliding door closes and leaves small gaps around the leaf. Hermetic sliding doors close and then seal, pressing the leaf against a gasket on the frame so that air, dust and draughts are held back. That one difference decides where each door belongs.

This guide compares hermetic sliding doors with standard automatic sliding doors: how each one closes, where each is the right choice, how they differ in activation, cleaning and maintenance, and how to tell which your room actually needs. MC Automations supplies, installs, commissions and services both: our MC-125 operator for automatic sliding doors and our MCL-165 for hermetic sliding doors.

Shut versus sealed

An ordinary automatic sliding door is designed to move people. It opens quickly, closes when the threshold is clear, and runs thousands of times a day. When it is closed there are working clearances between the leaf, the frame and the floor. Brushes reduce draughts, but the door is shut, not sealed.

A sealing door is designed to control air. As the leaf reaches its closed position it moves against the frame and compresses a gasket around its edges, so the closed door is windproof and dustproof. On our MCL-165 this is done by a sealing track system that brings the leaf onto the seals as it closes. It is a different mechanism from a standard sliding door, and the seal becomes a maintenance item in its own right.

Hermetic sliding doors compared with automatic sliding doors

• Purpose. Automatic sliding doors move people efficiently. Sealing doors control air, dust and draught between rooms.
• When closed. A standard door is shut with small clearances. A sealing door is pressed against the frame.
• Where they go. Standard doors suit entrances, lobbies, shops and offices. Hermetic sliding doors suit operating theatres, cleanrooms, laboratories, radiology, isolation rooms and controlled production areas.
• Activation. Standard doors usually open on a motion sensor as people approach. Sealing doors are often opened hands-free on purpose: elbow or foot switch, hands-free sensor, radar or remote, so the door only opens when someone means to go through.
• Speed and traffic. Standard doors are built for high traffic. Sealing doors open less often and are set for controlled, deliberate passage.
• Surfaces. Doors in clinical areas need flush, cleanable leaf faces that survive strong cleaning agents.
• Maintenance. Both need the running gear and sensors checked; sealing doors also need the seals and the sealing action checked.

Where hermetic sliding doors belong

Hermetic sliding doors are specified room by room, where controlling air leakage matters more than convenience.

• Operating theatres. Hands-free entry with the room’s air held rather than exchanged with the corridor.
• Cleanrooms. Controlled environments where air permeability is part of the specification.
• Laboratories. Separation between spaces held at different conditions.
• Radiology. Lead-lined leaves are available where shielding is required alongside the seal.
• Intensive care and isolation. Entrances that must seal reliably and open hands-free.
• Food and pharmaceutical production. Areas where dust and draught control is part of the process.

Our hermetically sealed doors page covers the MCL-165 specification, and the hermetic door brochure has the details in one place. For hospitals more broadly, our guide to hospital automatic doors explains how entrances, corridors and clinical rooms are treated differently.

Where a standard automatic sliding door is the better choice

A sealing door is not an upgrade for every opening. For main entrances, shopfronts, office lobbies, corridors and most internal doors, a standard automatic sliding door is the right answer: faster, simpler, cheaper to maintain and built for high traffic. Our automatic sliding doors page and the MC-125 operator page cover the options, with operators from R27 590 excl VAT.

Where the only need is to keep dust in one place, a well-detailed standard entrance with the right threshold and brushes may be the honest answer. We would rather tell you that than sell a more specialised door than the room needs.

What hermetic sliding doors are not

A sealing door is not a fire door and is not a substitute for one. Where a fire rating is required, that is a separate specification, and the building’s fire consultant decides what the opening needs. Our fire rated automatic doors page explains how those projects are handled.

We also do not publish laboratory certification or pressure-differential figures for the MCL-165, because we do not hold that documentation. If a project requires certified performance data, tell us at enquiry stage so the requirement is addressed before anything is ordered.

Activation: why hands-free matters

In clinical and controlled rooms, people’s hands are often full, gloved or clean. Sealing doors are usually opened by a deliberate hands-free action rather than by walking towards them, so the seal is only broken when someone actually needs to pass.

• Elbow or foot switch for staff carrying equipment or keeping gloves clean.
• Hands-free sensor that responds to a wave close to the switch rather than to movement in the corridor.
• Radar where approach detection suits the room.
• Remote for theatre staff or equipment movements.

Standard automatic sliding doors use similar sensors, set differently. Our guide to automatic door sensors explains how each type detects.

Cleaning and surfaces

The cleaning regime is often harder on these doors than the traffic is. Clinical surfaces are wiped down with agents chosen for what they kill, and over years that works on the leaf face, the frame, the seals and any exposed fixing. Flush leaf faces with no ledges, no exposed fasteners and no horizontal surfaces to collect dust make cleaning faster and keep the door looking right. Ask your infection-control team which agents are used before the leaf finish is chosen.

Maintenance: what is different

Both types need the running gear, the drive, the sensors and the safety settings checked on every visit. Hermetic sliding doors add the seal itself.

• Check the gasket for wear, tears, hardening and damage from cleaning agents.
• Check that the leaf closes fully onto the seal along every edge.
• Check the sealing track and its adjustment.
• Check hands-free switches and any interlocks with other doors.
• Re-check opening and closing force and safety sensing.

Our standard interval is every six months, and more often for doors that work harder. Our automatic door servicing page explains what each visit includes.

How to decide which door a room needs

Start with the room, not the door. Ask three questions.

• Does the room have to hold its air? If the specification for the room controls air leakage, dust or draught, hermetic sliding doors are usually the answer.
• Does the door need to open hands-free and deliberately? Clinical and controlled rooms usually do.
• Is the opening mainly about moving people? Entrances, lobbies, shops and corridors are, and a standard automatic sliding door suits them better.

If you are not sure, send us the room type, the opening size and what the room’s specification says about air and cleanliness. We will tell you plainly which door fits. Request a quote or call 010 412 0062.

Power cuts and emergency behaviour

Load shedding affects both door types. With a battery backup fitted the door keeps operating through an outage; without one it goes to the state chosen for the room. For sealing doors in clinical areas that decision needs extra care, because a door left open breaks the seal and a door left closed must still allow people out. Agree the behaviour with the building’s consultant. Our guide to automatic doors and load shedding covers the options. The South African Bureau of Standards publishes the SANS standards that apply to building work, and the consultant confirms what applies to each room.

Cost: what moves the price

Hermetic sliding doors usually cost more than a standard automatic sliding door of the same size, because the leaf, the sealing mechanism, the frame and the activation are more specialised. The main cost drivers are:

• Leaf construction and finish, and whether lead lining is needed for radiology.
• The opening size and whether the door is single or bi-parting.
• The activation devices and any interlocking with other doors.
• The frame and wall build-up around the opening.
• Access and working conditions, especially in live clinical areas.

Hermetic sliding doors are specified per room and confirmed from a site assessment, so we quote each project on its own requirements. Our automatic door prices guide explains how standard sliding doors are priced.

Installing hermetic sliding doors in live buildings

Most sealing doors go into hospitals, laboratories and factories that keep working while the door is fitted. Installation is planned around the building’s infection-control or process rules: screening the work area, controlling dust, working in agreed time windows and commissioning the door before the room goes back into use. We agree that plan with the facility team before the work starts.

A worked example: theatre, corridor and entrance

Consider a small private hospital with a main entrance, a corridor to the theatre suite and two operating theatres. The main entrance carries visitors, patients and staff all day, with trolleys and wheelchairs. It needs speed, wide opening and reliable presence sensing, so a bi-parting automatic sliding door on the MC-125 is the right choice, with a battery backup for load shedding.

The corridor doors into the theatre suite separate public and restricted areas. They need access control and controlled opening, but not necessarily a seal. A standard automatic sliding door with a card reader or hands-free switch usually serves.

The theatre doors themselves are different. The room’s air must be held, staff arrive with gloved or scrubbed hands, and the leaf faces are cleaned constantly. That is where hermetic sliding doors earn their place, opened by a foot switch or hands-free sensor and closed onto the seal behind every passage.

Three openings in one building, two different door types, and each chosen for what the room needs. That is the pattern we follow on every project.

Common mistakes when choosing between the two

• Specifying a sealed door everywhere. Using a sealing door on a busy corridor adds cost and maintenance without any benefit to the room.
• Using a standard door where the room must hold its air. Brushes reduce draughts but do not seal; a room with an air specification needs a door that seals.
• Motion sensors on a sealed door. If the door opens every time someone walks past in the corridor, the seal is broken all day. Use deliberate hands-free activation.
• Ignoring the cleaning agents. Leaf faces and seals must survive the cleaning regime. Ask infection control before choosing finishes.
• Treating a seal as a fire rating. A sealing door is not a fire door. Fire separation is a separate specification.
• Leaving interlocks to the end. Where two doors must not open at the same time, the interlock is designed in with the activation, not added later.

Retrofitting an existing opening

Many projects replace an existing manual or standard automatic door with a sealing one during a theatre or laboratory upgrade. The opening, the wall build-up and the floor all need checking, because a sealing door needs a frame it can seal against and a level floor at the threshold. Where the existing opening cannot take a sealing frame, we say so early and set out the options. Our upgrades and modernisation page explains how existing entrances are assessed.

Questions to ask any supplier

• Does the door seal when it closes, or does it only shut with brushes?
• Which activation devices are available, and can the door be interlocked with others?
• What finishes are offered, and will they survive our cleaning agents?
• Is a lead-lined leaf available if the room needs shielding?
• Is any performance data documented in writing, and for which conditions?
• Who services the door, how often, and are seals and parts held locally?

We answer those questions in writing for every project, including the ones where the honest answer is that a standard door will do.

Hermetic sliding doors and infection control

In hospitals, hermetic sliding doors are part of the infection-control plan rather than just a piece of hardware. They limit air movement between a theatre or isolation room and the corridor, they open without a hand touching a handle, and their flush faces are easy to clean. That is why hermetic sliding doors are agreed with the infection-control team as well as the architect. Ask the team which rooms need hermetic sliding doors, which cleaning agents they use, and how the doors should behave during an outage, and build those answers into the specification from the start.

Sliding door terms, explained

• Hermetic sliding doors. Automatic sliding doors that seal against the frame when closed.
• Gasket. The flexible seal the leaf presses against as it closes.
• Sealing track. The mechanism that brings the leaf onto the gasket at the end of its travel.
• Hands-free activation. Opening the door with an elbow, foot or wave rather than a handle.
• Interlock. A control that stops two doors opening at the same time.
• Lead-lined leaf. A leaf with lead shielding for radiology rooms.

Hermetic sliding doors: quick answers

• Hermetic sliding doors seal against the frame when they close; standard automatic sliding doors only shut.
• Hermetic sliding doors suit theatres, cleanrooms, laboratories, radiology and controlled production areas.
• Hermetic sliding doors are usually opened hands-free and deliberately.
• Hermetic sliding doors are not fire doors.
• Hermetic sliding doors need the seal checked on every service, every six months as standard.
• Hermetic sliding doors are quoted per room after a site assessment.

Hermetic sliding doors questions

Planning a theatre, laboratory or cleanroom? Send us the room type, the opening size and what the room’s specification says about air and cleanliness, and we will recommend the right door. Call 010 412 0062, Monday to Thursday 08:00 to 16:30 and Friday 08:00 to 14:00.