Guarding Elevator Machine Room Equipment: Hazards, Requirements, and Methods

Machine guarding (also called barrier guarding, or physical barriers) is a protective barrier placed on or around equipment, or between people and equipment, to keep workers from contacting moving parts and other hazards. In an elevator machine room, that means guarding the drive machine (the traction machine, in a traction installation), sheaves, ropes, brake, governors, and the rest of the rotating, moving, and energized equipment that shares the room with every mechanic, inspector, and building engineer who walks through the door.

The trade calls this work elevator guarding or elevator machine room guarding. A related requirement, elevator secondary guarding, covers the space beneath the machine room floor, where a false floor under the elevator machine gives access to the underside of the machine for maintenance. The car cables run through this space and can present cutting and abrasion hazards, sheaves there create nip and crushing points, and governor or selector equipment in the same area typically needs guarding as well.

This guarding is required by law in every US state and every Canadian province. Many building owners and managers don’t learn that until an inspector or a consultant’s report tells them. There is no grandfathering; the requirement applies to a 1920s machine room and a new one alike.

The requirement doesn’t come from the elevator code alone. The elevator safety code (ASME A17.1 in the US, CSA B44 in Canada, published jointly as one harmonized code) governs the elevator, and where other codes govern an aspect of the machine room, it defers to them. Its own maintenance-clearance provisions route electrical working space to the electrical codes, NFPA 70 in the US and CSA C22.1 in Canada. Worker protection works the same way. The general machine-guarding law of the land applies to the machine room as a workplace in its own right, with no exemption for elevator equipment: OSHA 29 CFR 1910.212 in the United States, and CSA Z432 with the provincial occupational health and safety regulations in Canada. The elevator code governs the elevator, the machine-guarding rules govern every machine, and the machine room contains both. In Ontario, the elevator regulator itself has closed the circle in writing: TSSA’s Director’s Order on alterations requires that added machine guarding conform to the elevator code’s maintenance-clearance and equipment-guarding provisions.

The requirement is specific. OSHA 1910.212 calls for one or more methods of guarding to protect workers from hazards such as point of operation, ingoing nip points, rotating parts, flying chips, and sparks, with guards affixed to the machine where possible and designed so no part of a worker’s body can reach the danger zone during operation. A machine room rarely has a point of operation in the production sense; the exposure is the rotating and moving equipment itself, which is what the standard’s other categories cover.

Seven hazard types account for essentially everything in an elevator machine room:

Every machine room should be hazard-assessed against this list before any guarding is fabricated. The right guarding for a 1960s geared traction room with a motor generator set is not the right guarding for a 2010s gearless room, and neither is a catalog product. That hazard assessment is the building owner’s or contractor’s responsibility, and MRG engineers the guarding to the hazards it identifies.

Every compliant machine room design is some mix of two approaches. The method is the same whether the room houses a geared or gearless traction machine.

Perimeter (global) guarding separates people from equipment zones with steel mesh barrier walls and access doors. It is fast to design and install, and well-suited to rooms where multiple machines cluster. This is MRG Global Guarding (GG series): custom-fabricated panels, posts, and door kits built to the room, with an Order Parts page for quantity reorders.

Component guarding puts an engineered guard on each individual hazard: sheave guards, brake guards, governor enclosures, belt covers. Its advantage is surgical. A technician removes one guard to service one component and stays protected from everything else in the room. This is MRG Component Guarding (CG series).

Most rooms end up with one approach or the other, though some require both: perimeter separation for the machine zone, with component guards where work happens inside it. Presence-sensing devices such as light curtains and switch mats exist as a third category on production machinery, but they depend on control-system integration and verification. In a machine room, fixed barrier guarding protects continuously without relying on a circuit, which is why it is the answer here. Which approach a room needs comes out of the survey.

Those are the essentials: what guarding is, why the room must have it, what it protects against, and the two forms it takes. The rest of this page is the deep reference: who enforces what, which code editions apply in 2026, and a component-by-component guide to guarding each piece of equipment in the room.

The laws above are performance-based. They mandate the outcome (workers protected from moving parts) and stop there. The labor regulator will not design your guarding, approve it in advance, or certify it after the fact. The elevator safety authority regulates the elevator, not worker protection, and will not sign off on guarding adequacy either. A locked machine room door does not count. Once a worker is through the door with equipment running, the hazard is live regardless of lockout/tagout procedures.

That gap between a mandatory outcome and no specified design is why machine rooms get cited, why guarding quality varies so widely, and why this page exists.

In 2009, an industry committee published a best-practices guideline for elevator machine room equipment guarding. The committee included regulators, Otis Canada, elevator contractor associations, consultants, and building owners, convened through Ontario’s elevator safety authority. MRG has hosted that document since publication, and you can still download the original PDF. It still circulates as a reference in the field, but it predates six editions of the elevator code and two editions of the machinery safeguarding standards, and it covers a single province. This page is its successor: the same component-by-component method, current code editions, and coverage of both the United States and Canada.

Every machine room falls under two separate regulators, and neither will do the other’s job.

The worker-safety regulator enforces machine guarding as a workplace safety matter: OSHA and the state OSH plans in the US, and provincial ministries of labour in Canada. This is where citations for unguarded equipment come from: 29 CFR 1910.212 and Subpart O in the US, and in Ontario, O. Reg. 851 Sections 24 and 25, with Sections 75 and 76 adding the requirement that maintenance happen only with motion stopped and equipment blocked or locked out.

The elevator safety authority enforces the elevator code, ASME A17.1/CSA B44, which governs the elevator itself: its own equipment-guarding provisions, working clearances, and what counts as an alteration. These are the state and municipal authorities having jurisdiction (AHJs) across the US, and TSSA in Ontario with equivalents in other provinces. Adding guarding to an existing elevator implicates this regulator too, and US and Canadian jurisdictions each apply their own alteration and permit rules.

The practical consequence is that guarding accepted by one regulator is not automatically acceptable to the other. A barrier that satisfies the labor inspector but blocks the elevator code’s required working clearances will fail. A code-compliant layout that leaves a sheave exposed will be cited. Guarding has to be designed to both at once, which is the core engineering problem this page addresses.

Confirm with your local jurisdiction. Code editions, adoption, and alteration-filing requirements vary by state, province, and city.

Five instruments do the work. MRG guarding is designed to this stack, and a letter of conformity documenting the design basis is available on request:

One point trips up owners constantly: the published edition is not the enforced edition. US states are spread across A17.1 editions from 2010 forward, adopted state by state and sometimes city by city. Ontario currently adopts ASME A17.1-2019/CSA B44:19 (CAD Amendment 295/22, in effect since August 2022). The edition enforced on your unit is the one your jurisdiction has adopted, so confirm it with your local jurisdiction before designing to a clause number.

Within the elevator code itself, two sets of provisions matter most. The equipment-guarding requirements for machine rooms and machinery spaces cover driving-machine sheaves and ropes, exposed gears, sprockets and selector drive components, and keys and screws in projecting shafts (2.10.1 in the editions Ontario and many US jurisdictions enforce). The maintenance-clearance requirements call for a clear path of not less than 450 mm (18 in.) to every component requiring maintenance, and the same clearance in the direction maintenance access requires (2.7.2). Access doors to machine rooms run 750 mm × 2030 mm minimum, and openings for access without full bodily entry are a separate, smaller class. Clause numbers are cited per A17.1-2019/CSA B44:19; confirm against your jurisdiction’s adopted edition.

Electrical codes add one more constraint that guarding routinely violates when nobody checks: minimum working space in front of disconnect switches and live controller faces. The elevator code routes this to the electrical codes. NEC Article 110 in the US starts at 3 ft of clear depth in Table 110.26(A)(1) and rises with voltage and conditions; in Ontario, the Ontario Electrical Safety Code sets 1000 mm, the value TSSA’s alteration order applies to guarding in front of control equipment. A screen erected inside that envelope fails even if every moving part is covered.

For the full standards picture across elevator and machine guarding, see the Compliance Guide.

The 2009 guideline’s most durable contribution was its method: go through the room component by component. The list below applies that method with one addition the original underweighted. For every component, the guard is only half the design. The other half is what the guard must not interfere with, because guarding that blocks inspection, lubrication, or service access does more than raise maintenance cost. It gets removed and left off, and then the room is unguarded again with paperwork saying otherwise.

Drive machine and drive sheave. Rotating sheaves and suspension ropes are the room’s defining entanglement and nip hazard, and the first items on the elevator code’s own guarding list. Barrier guards should be steel, perforated for visual inspection of ropes and sheave grooves, and sized to the reach-through rules (safety distances), where opening size sets the minimum distance from the hazard, the principle codified in ANSI B11.19 and CSA Z432. Two design realities catch first-timers. Ropes splay and draw: their lead angle off the sheave moves through the travel of the car, sometimes by more than 100 mm, so clearance must be designed to the extreme rope position rather than the parked one. Clear panels are also the wrong material near lubricated ropes, because lubricant spray coats them opaque. Guards should allow partial removal for rope and groove inspection without stripping the whole assembly.

Machine brake. Brake drums and shoe linkages present nip and crush hazards, and they are also among the most service-intensive items in the room: spring tension checks, periodic strip-down and overhaul, and continuous visual monitoring for oil fouling on the drum. Brake guarding must leave adjustment points reachable and the drum surface visible. A guard that has to come off for every brake inspection will live on the floor.

Drive motor. Hazards scale with vintage. Modern AC drive motors arrive well-enclosed and may need nothing added. Older DC machines need brush rigging accessible and visible, and any added guarding must not choke cooling airflow on motors without forced ventilation. Where guarding sits near live terminals, material selection has to account for the shock hazard.

Encoder and tachometer. Small component, real consequences: guarding must not disturb the tensioning that holds a rim-driven encoder against the sheave, and must not block sight of it, since encoder behavior is diagnosed by watching it run.

Motor generator set. Same profile as a DC drive motor (brushes, commutator, airflow, shock), mounted low enough to add a tripping hazard. Guard accordingly, and keep brush access and ventilation open.

Selector. Older installations’ mechanical selectors combine rotating drive components with live electrical elements, and their exposed gears, sprockets, drums, and drive tapes are named in the elevator code’s guarding list. Industry habit has long been to run them with the factory covers removed. The compliant approach is the reverse: original covers stay on as primary guarding (with tool-operated fasteners), and a planned secondary-safeguard procedure covers the servicing that must happen with covers off and power on.

Car and counterweight governors. Rotating sheaves and, on flyball designs, weights whose swing arc grows with speed, so guarding must clear the arc at tripping speed rather than at rest. Enclosures must leave switches, linkages, and the sealed spring assembly accessible. Governor settings are sealed by the elevator authority and seal integrity is checked at periodic inspection, so a guard that hides the seal creates an inspection problem of its own. Fully-enclosed modern governor designs may need no added guarding.

Rope gripper. Spring-applied and hydraulically released, often mounted in awkward access locations, with pads, cam surfaces, seals, and contacts that all need routine attention. A perforated screen sized to the sheave-guard rules works; design it for single-technician removal.

Deflector and secondary sheaves. Same hazard family as the drive sheave, frequently in low-overhead secondary spaces where a one-piece guard physically can’t be maneuvered out. Use sectional designs sized for one technician, no hoisting equipment, with lubrication points reachable and the same rope-twist allowance as above, especially on 2:1 roping.

Controllers and dispatch panels. The hazard is electrical, not mechanical: enclosures complete and closeable, high-voltage terminals shielded against incidental contact, and on vintage open-frame or slate-panel installations, proper cabinets retrofitted. Dispatch panels carry a trap: they may remain energized from a separate source when individual cars are shut down.

Hydraulic power units. Submersible units (the norm since the mid-1980s) enclose motor and pump in the tank, so there is generally nothing to add. Dry-type units are the exception that injures people: an exposed V-belt drive between motor and pump sheaves whose deep grooves shear rather than pinch. Factory panels stay on, and a perforated secondary guard over sheaves, belts, and shafts provides protection that survives the panels being off. It is perforated because belt condition and tension are checked visually with the unit running.

Machineroomless (MRL) installations. The drive equipment lives in the hoistway, but the same guarding logic applies to machinery spaces and control spaces, assessed per installation.

Across every component, the same requirements repeat. This is MRG’s working checklist: the 2009 committee’s principles plus what seventeen years of fabricating and installing this hardware has added. In Ontario, several of these are now written into the elevator regulator’s own alteration order.

Machine room equipment guarding protects workers from moving parts. The other guarding obligation on the same units is fall protection on the car top, governed across US and Canadian jurisdictions through the adopted edition of ASME A17.1/CSA B44 and jurisdictional retroactive requirements. The code requires a standard railing on every side of the car top where a 300 mm (12 in.) ball can pass between the car-top edge and the hoistway enclosure, and on sides with no hoistway enclosure at all. In Ontario, the retrofit wave began with TSSA Director’s Order 245/10, and the requirements have since carried forward into TSSA’s Code Adoption Document.

Where overhead clearance allows a fixed rail, MRG Fixed Car Top Rails (TOC-F) are the answer. Where low overheads make a fixed rail impossible, MRG Collapsible Car Top Rails (TOC-C) deploy for car-top access and fold flat in service, with position-monitoring safety switches supplied for integration into the elevator safety circuit. That is the design the code’s alteration provisions require for stowable railings.

The room dictates the design, so the work starts in the room rather than a catalog.

MRG fabricates guarding in service across the United States and Canada, for installations maintained by the major elevator OEMs and independent contractors alike.

Survey dimensions, photos, or your consultant’s hazard assessment: whatever you have. We’ll tell you what needs guarding, engineer the mix of perimeter and component guarding the room actually requires, and quote it.

Yes, in every US state and Canadian province. In the US, OSHA’s machine guarding requirements (29 CFR 1910.212) apply to rotating elevator equipment in machine rooms, backed by the General Duty Clause. In Canada, provincial occupational health and safety regulations such as Ontario’s Regulation 851, Sections 24 and 25, require exposed moving parts and nip hazards to be guarded. These rules apply to the machine room as a workplace in their own right; the elevator code governs the elevator and does not exempt its equipment from them. There are no grandfathering exemptions for older installations.

No. Restricted access limits who encounters the hazard; it doesn’t remove it. Once a worker is inside with equipment running, exposed sheaves, ropes, and rotating components are live hazards, and worker-safety regulators in both countries treat a locked door as access control, not guarding.

Both have a role, but they enforce different things, and the gap between them is why machine rooms end up under-guarded. The labor regulator (OSHA and state OSH plans in the US, provincial ministries of labour in Canada) enforces worker-protection guarding and issues the citations for exposed moving parts. The elevator safety authority (state and municipal authorities having jurisdiction, or AHJs, in the US, and TSSA in Ontario) enforces the elevator code, including its own equipment-guarding provisions, working clearances, and alteration-filing requirements when guarding is added. In practice, the elevator authority does not always enforce the worker-safety side of guarding, so passing an elevator inspection does not mean a room is compliant under labor law. Compliant guarding has to satisfy both, and neither regulator will design or pre-approve it for you.

The performance standards: ANSI B11.19 (current edition B11.19-2019, reaffirmed 2024) in the US and CSA Z432 (current edition Z432:23) in Canada. They govern guard construction, opening sizes, and reach-through distances, where the smaller the distance to the hazard, the smaller the permitted openings. The elevator code, ASME A17.1/CSA B44, adds elevator-specific requirements: which components must be guarded, the 450 mm maintenance path and clearance, and the working spaces guarding must not violate.

Newer equipment generally arrives better-enclosed, with modern drive motors, fully-enclosed governors, and submersible hydraulic units. But factory enclosure does not automatically satisfy worker-protection requirements for every hazard in the room, and most of the installed base predates these designs. Each room needs assessment against what’s actually in it.

Perimeter guarding separates people from equipment zones with barrier walls and access doors, which is efficient for rooms where machines cluster. Component guarding puts an engineered guard on each individual hazard, so a technician removes one guard for one task and stays protected from everything else. Most rooms end up with one approach or the other, though some require both. MRG fabricates both: Global Guarding (GG series) and Component Guarding (CG series).

Not without compensating protection. Both regimes require secondary safeguards when primary guarding is off and equipment must operate, worked out in advance with the maintenance provider rather than improvised at the machine.

Requirements vary by US state, so confirm with your local jurisdiction. In Ontario, adding guarding to an elevating device is a defined alteration: it is filed with TSSA as a design submission and performed by a registered elevator contractor using certified elevating devices mechanics, or under their direct supervision. MRG engineers and fabricates the guarding; installation is performed by qualified elevator personnel.

Engineered drawings produced from survey dimensions, work instructions for safe access posted at the guarding, and, available on request, a letter of conformity identifying the standards the guarding was designed to: OSHA 29 CFR 1910.212, ANSI B11.19, CSA Z432, and the applicable elevator code provisions.

It was never law. It is a reference document produced by an industry committee, and its component-by-component method remains sound. But it predates six editions of the elevator code and the current editions of the machinery safeguarding standards, and it covers a single province. MRG hosts the original PDF for reference, and this page carries its method forward against current requirements for both the US and Canada.

It is a different requirement on the same units. Car-top guardrails are fall protection: the elevator code requires a standard railing on every side of the car top where a 300 mm (12 in.) ball can pass between the car-top edge and the hoistway enclosure, with stowable designs permitted on existing cars where overhead conditions prevent a conforming fixed railing. In Ontario the retrofit requirements originated with TSSA Director’s Order 245/10, now carried in the Code Adoption Document. See MRG Car Top Rails, in fixed (TOC-F) and collapsible (TOC-C) configurations.