Frame vs ringlock scaffolding: 16 US systems on one house

Which US house and which 16 systems?

One small gabled house carries every system: 37 ft 5 in long and 17 ft 5 in deep (11.4 × 5.3 m), eaves at 14 ft 9 in (4.5 m), ridge at 19 ft 8 in (6 m). It is the same house the ScaFix system pages use, wrapped on all four sides, with no setting changed from the default. Because each run carries on round its corner, the scaffold is a little longer than the walls it covers. The inputs are the same for every system; where ScaFix has no maker’s rule for bays, bracing or ties, the text says so.

The comparison covers every US system in the ScaFix catalogue that produces a facade parts list: eight frame systems and eight modular ones. StepUp Shoring is left out because it is a shoring system for carrying loads, not an access scaffold. What the families are and where else they are used is explained in types of scaffolding; the European cuplock, ringlock and frame comparison on the same house is in cuplock vs ringlock vs frame.

How many parts does each US frame scaffold need?

Each row adds up to its pieces cell. The frame column counts full frames and the short 1 m (3 ft 3 in) frames that make up height; the guardrail column includes a rail in the bottom field of every bay, a ScaFix stiffening rule the methodology explains. Scaffold area is the elevation from the ground to the top of the scaffold, overhang included.

How many parts do the US ringlock, cuplock and wedge systems need?

Here too every row sums to its total. Most of the modular lists share the same skeleton, 120 standards and 156 ledgers and transoms over 16 bays, so the totals split on three things: bracing, ties and, for SafLock, the bay grid.

Why do US frames need half the pieces?

A frame is two posts and a bearer welded into one part. Waco’s RED frames are 5 ft wide and 6 ft 7 in tall, and its narrow frames 2 ft 3⅝ in wide; the Waco name goes back to 1945, and BrandSafway is now the exclusive supplier (WACO RED brochure ORN1701, pp. 2–4). StepUp lists walk-through frames 3 ft, 42 in and 5 ft wide at 6 ft 4 in and 6 ft 7 in (StepUp Frame & Brace catalog, p. 6). On this house that means 44 to 56 frames (58 to 66 with the top-lift posts) where a ringlock needs 120 standards plus 156 ledgers and transoms.

Frames spend their pieces on bracing instead. Under 29 CFR 1926.452(c)(2) frames and panels must be braced by cross, horizontal or diagonal braces, and under (c)(3) joined vertically by coupling or stacking pins. ScaFix puts a cross brace on both faces of every bay and lift, which is why Waco’s 17 bays on two lifts come to 68 braces. Waco Frame also has the most bays, 17, because ScaFix plans it on 10, 7 and 5 ft spacings only; the others add 8 ft bays and fit each wall with fewer. Waco also sells 8 ft cross braces (ORN1701, p. 7); ScaFix’s Waco Frame entry does not use them yet, which costs it one bay and 4 braces.

Frame height sets the deck levels. The 6 ft 7 in Waco frames put the decks at 8 ft 2 in and 14 ft 9 in (2.49 and 4.5 m); the 5 ft tall Saferstack Mason frames at about 7, 12 and 17 ft (2.12, 3.65 and 5.17 m), the top one on the gables.

Why does SafLock need 20 bays?

SafLock is a rosette system: BrandSafway says each rosette holds up to eight connections, with no loose nuts, bolts or clamps, and that it is used throughout Canada (BrandSafway, SafLock). Its count is high for a geometric reason. ScaFix plans SafLock on 3.05, 2.13, 1.57 and 1.15 m ledgers (10 ft, 7 ft, 5 ft 2 in, 3 ft 9 in) and no 8 ft bay, so each long wall takes six bays and each gable four: 20 bays against 16. Four more bays add 24 standards, 36 ledgers and transoms, 24 guardrails and 8 base jacks, before anything else differs. Even SafLock’s narrowest width, 1.15 m (3 ft 9 in), is wider than the 0.73 m rosette systems.

What separates the other modular systems?

The node is the main design difference:

• Rosettes. AT-PAC, headquartered in Roswell, Georgia, puts a rosette every 50 cm with four small holes at 90° and four larger ones for other angles, and says its Ringlock has DIBt certification (AT-PAC Ringlock). StepUp prints its RingLock horizontals in feet and millimetres, 10 ft = 3,050 mm (StepUp RingLock catalog, p. 5). Bil-Jax, which calls itself an American-made scaffolding manufacturer (Bil-Jax), sells Ring Lock horizontals by the foot, so ScaFix plans exact feet; on this house Bil-Jax and StepUp RingLock give the same totals with slightly different part lengths.
• Cups. Excel verticals carry cups every 5.75 in (Excel technical manual, Rev. AL, PDF p. 15); StepUp also sells a cuplock line (StepUp Cuplock catalog).
• Wedges in ring sets. BrandSafway’s Systems Scaffold hooks each horizontal or diagonal onto ring sets placed every 21 in up the post and locks it by hammering home a wedge (Systems Scaffold guide ORN 210, pp. 4–5). Its 9 ft and 6 ft bays overrun the walls a little more, hence the largest area.

The brace column is where the modular lists part company. Excel asks for bracing on one bay for every 30 ft of scaffold, generally every fourth bay, on the inside and outside rows, from the bottom to within 10 ft of the top (technical manual, PDF pp. 46–47). ScaFix applies a similar end-bay and every-fourth-bay rule on both faces to SafLock, Bil-Jax and StepUp, 40 braces each. AT-PAC is braced every fourth bay from the Doka Ringlock documents, which cover the same system (12), Safway Systems gets 16, and Catari, for which ScaFix has no maker’s rule, falls back on a general ringlock rule with 8. Check the bracing against the manual of the system you actually rent.

How many planks does a deck unit mean?

ScaFix counts one deck unit per bay and level. Turn it into planks with the width you stock: Metaltech recommends three 19 in platforms side by side on its exterior frames, a 57 × 84 in working deck rated 75 lb/ft² (Metaltech, 2022), so 30 Saferstack deck units mean about 90 planks of the right length. StepUp’s RingLock catalog lists steel planks 9 in and 12.5 in wide (pp. 10–11). Whatever the plank, 1926.451(b)(1) requires each working level to be fully planked with gaps of no more than 1 in, and the SSFI guidelines printed in Waco’s brochure ask timber planks to overlap at least 12 in and run 6 in beyond the centre of the support, or be cleated (p. 20).

Why do the tie counts differ?

OSHA ties a supported scaffold once its height passes four times its base width, then every 20 ft on scaffolds 3 ft wide or less, 26 ft on wider ones, at no more than 30 ft along and with the top tie no further than the 4:1 height from the top; the full rule is in OSHA scaffolding requirements. What moves the counts on this house:

• Width. A 2 ft 3⅝ in WACO Narrow frame reaches 4:1 at 9 ft 2½ in, so it gets 32 ties against 22 on the 5 ft Waco Frame. StepUp Frame & Brace, at 3 ft, falls in the 20 ft class.
• Bay layout, not a different grid. ScaFix ties all three 5 ft Waco frames on the same planning grid, rows about 13 ft (4 m) apart and ties about 20 ft (6 m) apart along the run, closer than the regulation. Waco Frame’s 22 against 24 for the RED frames comes from where its bays and wall ends fall.
• AT-PAC. Doka’s Ringlock is based on the AT-PAC Ringlock system and cites its DIBt approval Z-8.22-992 (Doka Ringlock user information, p. 8; Z-8.22-992), and Doka has owned AT-PAC outright since 2023 (Doka). ScaFix follows Doka’s anchor grid: 8 m offset over height plus at least one V-anchor every five bays (p. 75), hence 29 ties and 8 couplers.
• Excel. ScaFix takes Excel’s 2 ft bearer as the base, which brings the first 4:1 tie down to 8 ft, hence 24.
• No maker’s rule. For Bil-Jax, SafLock and Catari, ScaFix has no published tie rule from the maker and applies its own planning grid.

Sheeting, which needs far more ties, is covered in scaffold ties and anchoring.

Can you mix brands on one scaffold?

Only within narrow limits. 1926.451(b)(10) bars mixing components from different manufacturers unless they fit together without force and the user keeps the structure sound, and the SSFI guidelines in Waco’s brochure say frames and components of different makers shall not be intermixed. Identical totals for Bil-Jax and StepUp RingLock do not make their parts interchangeable.

Which system for a house, a plant or an interior job?

• Houses and low-rise facades: a frame system, with the fewest pieces to haul and count. The rails still follow the 38 to 45 in toprail rule, see scaffold guardrail height.
• Plants, refineries, round tanks, heavy loads: a modular system. Excel and Systems Scaffold aim at plant work with tube-and-clamp tie-offs to structural steel, and the rosette systems take any angle.
• Small interior jobs: what people search for as baker scaffolding is a small rolling platform rather than a facade system; Bil-Jax lists its Pro-Jax at 4 ft high, 6 ft long and 29 in wide. Rolling units follow the tower rules in mobile scaffold towers.

How ScaFix fits in

ScaFix is a planning tool that turns wall dimensions or a PDF drawing into a 3D scaffold and a parts list for many systems, including all sixteen here. The Waco Frame, Bil-Jax Ring Lock and SafLock pages show the full lists. It is not a structural design.

This is planning information, not structural approval. The manufacturer’s instructions and 29 CFR 1926 Subpart L, or your state plan, decide how a scaffold is built, braced and tied; a qualified person designs it under 1926.451(a)(6), and a competent person inspects it before each work shift under 1926.451(f)(3).

Frequently asked questions

Sources

Primary sources used for this article, with the date each was read.

• WACO RED frame scaffolding and shoring brochure ORN1701 (BrandSafway, 2020) (read 24 October 2026)
• StepUp Frame & Brace catalog (updated February 2024) (read 24 October 2026)
• StepUp RingLock catalog (updated February 2024) (read 24 October 2026)
• StepUp Cuplock catalog (updated February 2024) (read 24 October 2026)
• Excel Modular Scaffold Standard Component Technical Manual, Rev. AL (read 24 October 2026)
• BrandSafway Systems Scaffold Product Selection Guide (ORN 210, 2018) (read 24 October 2026)
• BrandSafway: SafLock system scaffold (read 24 October 2026)
• AT-PAC: Ringlock scaffolding system (read 24 October 2026)
• Doka: Ringlock User Information, instructions for assembly and use 999817902 (09/2023), pp. 8 and 75 (pdf) (read 24 October 2026)
• DIBt Z-8.22-992: scaffold components for the modular system AT-PAC RINGLOCK, Atlantic Pacific Equipment (12 April 2024) (pdf) (read 24 October 2026)
• Doka: Doka completes the 100% acquisition of AT-PAC (2 February 2023) (read 24 October 2026)
• Metaltech: Safety work at height (13 October 2022) (read 24 October 2026)
• Bil-Jax: scaffolding manufacturer, product listing (read 24 October 2026)
• 29 CFR 1926.451, General requirements for scaffolds, via Cornell LII (read 24 October 2026)
• 29 CFR 1926.452, Additional requirements for specific types of scaffolds, via Cornell LII (read 24 October 2026)