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Quick Verdict

Specify a floor closer when the leaf is all-glass or has no rail for a closer arm, must swing both ways, may show nothing on its face or header, or outweighs what butt hinges and a surface closer should carry. A dormakaba BTS80 controls 660 lb and 4'-6" of width from a 2-3/8" case; a BTS75V controls 260 lb from a 2" case for thin slabs. Center-hung hardware (BTS80A, Rixson 370, Ives 7255) is the answer for double-acting and glass doors; 3/4" offset hardware (BTS80D, BTS75V, Rixson 195 or 117, Ives 7226) is the answer when the door needs a stop, a weatherstrip, or a fire label. Exceptions: a retrofit on a slab with no cement case usually goes to offset pivots plus a surface closer, and a labeled opening never gets a center-hung set, a double-acting closer, or a mechanical hold-open.

When does a floor closer beat a surface closer?

A surface closer is sized by door width (ANSI/BHMA A156.4 sizes 1 through 6) and assumes the hinges carry the leaf. A floor closer does both jobs: its spindle is the bottom pivot, so the body that controls the swing also carries the weight on a bearing.

The floor closer wins in four cases. All-glass doors have no stile for an arm or a hinge; the spindle engages a bottom patch fitting, a top pivot engages the top patch, and nothing else touches the glass (exit hardware for them is covered in the guide to panic bars for glass storefront doors and gates). Double-acting doors need a closer that works in both directions, and every surface closer is single acting. Monumental bronze or oversized hollow metal doors exceed what a hinge and a size 6 arm should carry; the BTS80 is rated for 660 lb. And where nothing may show on the door or header, only a cover plate shows.

The surface closer wins on retrofit, service, and budget: cutting a 2-3/8" pocket into a finished slab costs more than the hardware, a body swap means pulling the door, and a BTS80A alone is about $1,707 at NLS before top pivot, threshold, and slab work. The right arm for a single-acting door is covered in the sibling guide to door closer arm types and mounting options. An overhead concealed closer (header-mounted, no floor cut) is a different product with its own overhead concealed door closer specification guide.

Center-hung vs offset pivots: which one does the door and frame dictate?

A center-hung pivot puts the axis inside the door, centered in its thickness and set in from the heel: Ives calls for the pin centerline 1-3/4" minimum from the jamb and a radiused heel of 1-5/8" minimum. The heel sweeps through the plane of the frame, so the door can swing both ways, there is no stop at the heel to hold a weatherstrip, and no center-hung set here is offered for a labeled opening (the Rixson 370 listing bars it from labeled doors and frames).

An offset pivot puts the axis outside the door, 3/4" from the face. The door swings like a hinged door: single acting, closing against the frame stop, taking a full weatherstrip and a saddle threshold, and carrying a fire label when the pivots are listed. The edge is beveled 1/8" in 2" instead of radiused. Where the bottom pivot lands decides a retrofit: floor (Rixson 117, L117), side jamb (Rixson 195), or a surface base plate (Ives 7226 BTM). The 1-1/2" offset (BTS80C) moves the axis a further 3/4" out for doors and frames prepped for it and is not interchangeable with 3/4" prep.

The rule: existing prep dictates on a replacement; on new work, double acting or glass means center-hung, and exterior, weatherstripped, or labeled means offset.

dormakaba BTS80 and BTS75V floor closers decoded

All four units NLS stocks are cam-and-roller closers certified to ANSI/BHMA A156.4 Grade 1 and ship with the 3/4" spindle (part 74010), with interchangeable spindles for other floor heights. The letter after BTS80 says how the door hangs.

Model	Hung and acting	Offset	Spring size	Hold-open (series spec)	Max door weight	Max width interior / exterior	Case depth
BTS80A SZ4, aluminum door and frame	Center-hung, double acting	None	4	Multipoint 75° to 175°	660 lb	4'-6" / 4'-0"	2-3/8"
BTS80D SZ4	Offset-hung, single acting	3/4"	4	Multipoint 75° to 175°	660 lb	4'-6" / 4'-0"	2-3/8"
BTS80C SZ4	Offset-hung, single acting	1-1/2"	4	Multipoint 75° to 175°	660 lb	4'-6" / 4'-0"	2-3/8"
BTS75VD	Offset-hung, single acting	3/4"	1 to 4, adjustable	Non-hold-open, no delay	260 lb	3'-6" / 3'-0"	2"

Size 4 is the ANSI spring size, rated for 2'-6" to 4'-0" interior and 2'-6" to 3'-6" exterior widths; 660 lb and 4'-6" are the body's limits, and a wider leaf needs a different spring, quoted by the desk. The BTS80 body adds selectable delayed action from 175° to 75°, mechanical backcheck at about 70°, a pressure relief valve against forced closing, and case adjustment of 1/4" lateral and longitudinal plus 5/32" in height. The BTS80A SZ4 double-acting closer for aluminum door and frame is the storefront and glass unit; the BTS80D is the same body for a single-acting 3/4" offset door, the BTS80C the 1-1/2" offset version.

The BTS75VD non-hold-open floor closer is the thin-slab unit, not the budget BTS80: 2" case, 260 lb, 3'-6" interior and 3'-0" exterior width, a spring adjustable across sizes 1 to 4 (settable to the 8.5 lb exterior opening-force limit), and a UL listing for fire-rated doors when an auxiliary stop limits the swing to 175°. At about $1,664 at NLS it costs nearly what a BTS80A does; pick it for slab depth and door weight, never for the few dollars between them.

Pivot sets and weight ratings: Rixson, Ives, and when you need an intermediate

A pivot set carries the door but does not close it: pair it with a surface closer or an overhead concealed closer, or let a floor closer's spindle replace its bottom pivot. Weight, not width, is the rating most installers guess. Take it from the door cut sheet; 1/2" tempered glass runs about 6.5 lb per square foot, so a 3'0" by 8'0" leaf is roughly 160 lb before rails and patches.

Set	Type	Max door weight	Max door size	Top pivot	Bottom pivot	Intermediate	Fire label
Ives 7253 SET	Center-hung, non-handed	300 lb	4'0" x 8'0"	7253 Top, header mount	7253 Btm, base plate	None	Not listed
Rixson 370	Center-hung, non-handed	500 lb	3'8" x 8'6"	340, included	Mounts directly to floor	None	Not allowed on labeled doors
Ives 7255 SET	Center-hung, non-handed	500 lb	4'0" x 8'0"	7255 Top, header mount	7255 Btm, base plate	None	Not listed
Rixson 117	3/4" offset, interior, handed	300 lb	3'6" wide	180, included	Mortised into floor	119 recommended	Not listed
Rixson 195	3/4" offset, jamb-mounted, handed	450 lb	4'0" wide	180, included	Mortised into side jamb	119 or M19 recommended	Fire rated
Ives 7226	3/4" offset, Btm non-handed	600 lb	Not listed	7226 top, ordered separately	7226 Btm, base plate	7226 INT, handed, UL 10C 20 min	Btm sold non-fire-rated; INT UL 10C listed
Rixson L117	3/4" offset, lead-lined, handed	1,750 lb	4'0" wide	L180, included	Mortised into floor	ML19 required	Not listed

The Rixson 370 center-hung pivot set with 340 top pivot is Grade 2 under A156.4 with sealed bearings and is about $462 at NLS; the Ives 7255 center-hung pivot set is cast brass with 3/16" to 3/4" of floor clearance set by the mortise depth, about $350. On the offset side the Rixson 195 fire-rated offset pivot set is the retrofit answer: 450 lb, bottom pivot in the side jamb rather than the floor, 3/16" of vertical adjustment after installation without shims.

Intermediate pivots stop being optional with height or weight. Rixson: doors 60" to 90" tall take one, and each additional 30" warrants another. Ives: one over 7'0" and one every 2'6" as needed, plus one for every 100 lb over the set's limit. The Ives 7226 INT is handed, UL 10C listed for 20 minutes, and the piece Ives cites for NFPA 80 fire door applications. A sagging door that stays on butt hinges wants a Hager 253 2C reinforcing pivot, not a pivot set.

How to replace a failed floor closer without cutting the slab

Match six things to the body in the floor before ordering: acting (single or double); hung (center, 3/4" offset, or 1-1/2" offset); spring size; spindle (3/4" standard, length set by finished floor and threshold height above the case); hold-open (a labeled door gets a non-hold-open unit); and handing. The BTS80C, BTS80D, and BTS75VD are handed units (the BTS75V body itself is not); the double-acting BTS80A is not handed. The guide to door handing for commercial hardware settles LH, RH, LHR, and RHR.

A BTS80 body drops into a BTS80 case, and the case adjustment absorbs what the old pour got wrong. If the case is another make, the footprint differs: cut the slab for a new case, send the desk the case dimensions for a cross-reference, or leave the floor alone and hang the door on a Rixson 195 with a surface closer. Reuse a sound top pivot: the Rixson 340 tops the 370 and 117-3/4 sets and the 28, 30, 40, and 50 series Rixson floor closers, the 180 tops most offset sets and floor closers.

Finish with the stop: dormakaba's instruction is that an auxiliary stop goes in whenever hardware or adjacent structure interferes with maximum opening, because the pressure relief valve protects the body, not the door or frame. The sibling guide to overhead door stops and holders covers the options.

Fire rating, ADA opening force, and what the threshold has to do

NFPA 80 requires a fire door to close and positively latch; a double-acting leaf has no stop to latch against, so the BTS80A never goes on a labeled opening, and the 370 listing rules out that center-hung set. That leaves offset hardware with a listing: the Rixson 195 (fire rated), the Ives 7226 INT (UL 10C, 20 minutes), and the BTS75VD non-hold-open closer with an auxiliary stop at 175°. Hold-open on a fire door is permitted only when the fire alarm or a smoke detector releases it; the BTS80's mechanical multipoint hold-open is not that device.

ADA sets the other limit. Under ADA 404.2.9 an interior hinged door opens with 5 lbf maximum; the standard sets no exterior figure, hence the 8.5 lb exterior limit dormakaba quotes, and fire doors are allowed the force their listing needs to latch. Under 404.2.8.1 the door takes at least 5 seconds from 90° to 12°, the sweep valve's job. A spring that closes a 500 lb exterior door against wind rarely stays under that limit; the answer is a low-energy power operator. The guide to ADA compliance for commercial door hardware covers the rest.

A center-hung door sweeps through the frame, so it takes no stop-mounted weatherstrip, only a sweep, pile at the jambs, and a cover plate flush in the threshold line: fine under a canopy, poor on a wind-driven-rain elevation. An offset door closes against a stop and takes a full weatherstrip, saddle threshold, and sweep. Either way the threshold stays at 1/2" maximum under ADA 404.2.5, and a case that fills with de-icer water takes the seals with it.

Common mistakes with floor closers and pivots

1. Sizing a pivot set by width and never weighing the leaf.

2. Putting a center-hung set or a double-acting closer on a labeled door.

3. Ordering a multipoint hold-open BTS80 for a fire door instead of a non-hold-open unit.

4. Skipping the intermediate pivot on a door over 7'0" or over the set's weight limit.

5. Ordering 3/4" offset hardware for a door and frame cut for 1-1/2", or the reverse.

6. Guessing the hand on an offset closer or pivot set.

7. Radiusing a heel that should be beveled 1/8" in 2", or the reverse.

8. Choosing the BTS75V for a 400 lb door because it is a few dollars cheaper; it is the 260 lb unit.

9. Ordering the body without spindle length, cover plate, and threshold for the finished floor.

FAQ

Can a floor closer go into an existing slab? Yes, if you cut a pocket for the cement case: 2-3/8" deep for a BTS80, 2" for a BTS75V. If the floor cannot be opened, a Rixson 195 with the bottom pivot in the jamb plus a surface closer keeps the door hung without touching concrete.

Do I need a floor closer with a Rixson 370 or Ives 7255? No. Those sets carry the door and need a separate closer, surface or overhead concealed. If the closer must hide in the floor, the BTS80A replaces the bottom pivot.

How many intermediate pivots does a 9'0" door need? Two by the Rixson rule (one for 60" to 90", one more per additional 30"); the Ives rule (one over 7'0", one every 2'6" as needed) gives the same count, plus one for every 100 lb over the set's rating.

Which pivot sets are fire rated? The Rixson 195 is sold as fire rated and the Ives 7226 INT is UL 10C listed for 20 minutes; the 370 is barred from labeled doors. The 7255, 7253, 117, and L117 listings state no rating; ask the desk for the listing sheet.

Next step

Send the desk six things: door weight, width and height, thickness and material, single or double acting, whether the opening is labeled, and a photo of the existing cover plate and body label. The desk returns closer body, spindle length, cover plate, top pivot, and threshold as one order. Browse the floor concealed closers category for the BTS80 and BTS75V bodies, including the BTS80D SZ4 3/4" offset floor closer for single-acting doors, and the commercial door pivots category for Rixson and Ives sets, tops, and intermediates. Orders placed before 3:00 p.m. EST ship the same day by UPS or FedEx from the Brooklyn warehouse, ground shipping is free at $450 and up, and stock items return within 30 days in saleable uninstalled condition (15% restocking). Call 718-814-6300 with the case label and the door schedule line.