The Invisible Door Closer: A Guide to dormakaba Floor Springs and Accessories
When designing or maintaining a commercial space, high-end residential property, or public building, door control is a critical consideration. While overhead door closers are highly common, they aren't always the best fit. For minimalist glass entrances, heavy timber doors, or double-action doors that need to swing in both directions, a concealed solution is required.
This is where floor springs come in. Installed flush within the floor cavity, floor springs provide powerful, reliable door control while remaining virtually invisible.
As a global leader in access solutions, dormakaba manufactures some of the most durable and highly engineered floor springs on the market. However, choosing the right floor spring, door straps, and top centres for your specific door setup can feel like solving a complex puzzle.
In this buying guide, we will break down the dormakaba floor spring range, explain the difference between single and double-action setups, and help you select the exact components you need for a seamless installation.
Step 1: Choosing the Right Floor Spring
The floor spring itself is the powerhouse of the system, housing the hydraulic mechanism that controls the door's opening and closing speed. dormakaba offers several models tailored to different door weights, widths, and functional requirements.
dormakaba BTS75V: The Versatile All-Rounder
The BTS75V is the go-to floor spring for the vast majority of standard to heavy-duty installations. It is a highly adaptable, universal unit suitable for both single and double-action doors up to 120kg in weight and 1100mm in width. Its standout feature is adjustable spring strength, allowing installers to fine-tune the closing force to suit the specific door size and environment.
- Standard BTS75V: Ideal for standard applications requiring reliable, controlled closing.
- BTS75V Hold-Open: Perfect for busy corridors or retail entrances where you want the option to keep the door mechanically held open at a 90-degree angle during peak traffic hours.
- BTS75R: A specialized variant designed to offer robust, non-handed performance across a variety of demanding door configurations.
dormakaba BTS80 EMB: The Heavy-Duty Fire Safety Solution
For exceptionally heavy doors or applications where life safety and fire compliance are paramount, the BTS80 series is the industry benchmark. The BTS80 EMB features an electro-magnetic hold-open function powered by a 24V DC supply. This allows the door to be held open for daily convenience but ensures it releases and self-closes automatically upon fire alarm activation, making it a crucial component in commercial fire barrier strategies.
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Step 2: Single-Action vs. Double-Action Setups
Before purchasing your accessories, you must identify how your door operates:
- Single-Action Doors: These doors open in one direction only (usually pushing inward or pulling outward) and close flush against a door stop.
- Double-Action Doors: These doors can swing both inward and outward (common in restaurant kitchens, hospital corridors, and busy office partitions) and rest in the centre when closed.
Your choice here dictates the physical hardware - specifically the straps (attached to the bottom of the door to connect it to the floor spring spindle) and the top centres (which guide the top pivot point of the door).
Step 3: Selecting Your Straps, Pivots, and Top Centres
Because floor springs are concealed, they rely on a system of heavy-duty pivot points rather than traditional butt hinges. Here is how to select the right accessories for your door type:
For Single-Action Doors
If your door only opens one way, you require hardware engineered for flush-closing, single-action doors.
- Bottom Connection: The dormakaba 7411/56 Single Action Door Strap is a heavy-duty bottom strap designed to link your timber or metal door directly to the spindle of a BTS series floor spring.
- Top Connection: To secure the top of the door, use the dormakaba 7411K/56F Single Action Top Centre, which provides a robust, smooth-rotating top pivot point.
For Double-Action Doors
Double-action doors require hardware that allows a full 180-degree swing (90 degrees in each direction).
- Bottom Connection: The dormakaba 7421 and 7422 Universal double-action door straps are drop-forged steel bottom straps engineered specifically for double-action timber doors. For heavier commercial double-action doors paired with the BTS80 floor spring, the dormakaba 8021 Double Action Strap offers maximum durability.
- Top Connection: The dormakaba 8066 Double Action Top Centre Complete Unit is the industry standard for timber doors, ensuring the top pivot remains perfectly aligned and secure during constant back-and-forth movement.
Standalone Pivot Bearings
If you do not require a self-closing floor spring but still want to hang a heavy door on a pivot system, dormakaba's floor pivot bearings are the ideal solution. The 7471AX (Square) and 7475AX (Rectangular) floor pivot bearings are heavy-duty, rust-protected bottom pivots designed to support demanding door weights without the hydraulic closing mechanism.
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Step 4: Simplify with Complete Fitting Kits
If you are installing a new door from scratch, buying individual components can be daunting. To eliminate the guesswork, we offer complete, pre-configured fitting kits that bundle the essential hardware you need into a single package.
- dormakaba BTS75V Single Action Kit: Includes the BTS75V floor spring along with the necessary single-action strap and top centre.
- dormakaba BTS75V Double Action Kit: Bundles the BTS75V floor spring with double-action hardware, perfect for double-swing timber doors.
- dormakaba BTS80 Double Action Kit: A premium, heavy-duty accessory pack designed to suit the powerful BTS80 floor spring, ensuring your heavy double-action doors operate flawlessly.
Summary: How to Plan Your Installation
To ensure a successful floor spring installation, always follow these four steps:
- Weigh and measure your door: Ensure your door falls within the limits of the floor spring (e.g., up to 120kg for the BTS75V).
- Determine the action: Decide if your door is single-action (one-way) or double-action (two-way).
- Select the correct accessories: Match your door action to the corresponding dormakaba straps and top centres, or opt for a complete fitting kit.
- Don't forget the finishing touches: Accessories like the dormakaba 7483 Cover Caps provide a clean, professional finish to cover the top centre mechanism, protecting it from dust and completing the high-end look.
By choosing genuine dormakaba hardware, you are investing in a discreet, long-lasting, and highly reliable door control system that will keep your doors operating smoothly for years to come.
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