Machinery Alignment JHA (Job Hazard Analysis / Activity Hazard Analysis)
Updated 2026-06-23
A Machinery Alignment JHA (Job Hazard Analysis / Activity Hazard Analysis) is the plan that keeps the millwright performing precision alignment from being caught in machinery that starts unexpectedly, pinched during the fine adjustments, or injured by the stored energy in the drivetrain. Machinery alignment is the precision task of aligning a driver and driven component — a motor and pump, a motor and gearbox — so their shafts are concentric, work that requires the machine to be safely de-energized and locked out while the millwright works close to the coupling and rotating parts. This guide walks through building a Machinery Alignment JHA that names the stored-energy, rotating-equipment, and pinch hazards and assigns the lockout, rotation, and adjustment controls that hold up in the field.
Why machinery alignment needs its own JHA
Machinery alignment — shaft alignment between a driver (motor) and driven equipment (pump, fan, compressor, gearbox) — is precision work done close to the coupling, shafts, and machine, with the millwright making fine adjustments, taking measurements, and sometimes rotating the shafts by hand. The hazards are specific: the machine starting unexpectedly while the millwright's hands are near the coupling and rotating parts, the stored energy in the drivetrain and connected systems, pinch and crush points at the coupling and during the jacking and shimming adjustments, and the connected process and electrical systems. Because the work puts the millwright in close contact with machinery that must not move, it warrants a dedicated JHA built on lockout/tagout.
Breaking machinery alignment into steps
The steps for a Machinery Alignment JHA follow the alignment:
- Identify the machine's energy sources and connected systems
- Lock out and verify zero energy before any alignment work
- Release or restrain stored energy in the drivetrain and systems
- Set up alignment tools and take initial measurements
- Make adjustments — jacking, shimming, moving the machine
- Rotate shafts by hand only with the machine locked out
- Verify the alignment and tighten connections
- Remove locks and return to service under control
Each step carries a hazard, and the lockout/verification and the close-contact adjustment work are where the most serious risks are controlled.
The hazards step by step
Unexpected startup
The defining hazard is the machine starting while the millwright's hands are near the coupling, shafts, or rotating parts during alignment. An unexpected start would catch the worker in the rotating equipment. The controls are lockout/tagout of the machine and its driver before any alignment work, verifying zero energy before contact, each worker applying their own lock, and never working on alignment with the machine capable of starting. The machine stays locked out throughout the alignment, including when shafts are rotated by hand.
Stored energy in the drivetrain and systems
The drivetrain and connected systems can store energy — rotational inertia, spring tension, hydraulic and pneumatic pressure, and the energy of connected process systems — that can move the machine or its components. The controls are releasing or restraining stored energy before alignment, blocking components that could move, and relieving pressure in connected systems. (These follow the LOTO fundamentals.)
Pinch and crush during adjustment
Aligning the machine involves jacking, shimming, and moving the equipment, and rotating shafts and handling the coupling — all creating pinch and crush points for hands and fingers. The controls are using jacking and adjustment tools rather than fingers, keeping hands clear of the coupling and pinch points, controlled movements during jacking and shimming, and care when rotating shafts by hand (with the machine locked out and hands clear of pinch points).
Connected systems and rotating equipment
The machine connects to electrical, process, and mechanical systems, and even locked out, care is needed around the equipment. The controls are isolating all connected energy sources, confirming the machine cannot be started by any control or automatic signal, and standard care around the equipment.
A simple Machinery Alignment JHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Identify energy | Missed source | Map all energy sources and connected systems | OSHA 1910.147(c) |
| Lock out | Unexpected startup | LOTO machine and driver, each worker's own lock | OSHA 1910.147(d) |
| Verify zero energy | Assumed-dead error | Verify zero energy before any contact | OSHA 1910.147(d)(6) |
| Release stored energy | Drivetrain movement | Release/restrain stored energy, block components | OSHA 1910.147(d)(5) |
| Adjust alignment | Pinch / crush | Jacking tools, hands clear of coupling, controlled moves | OSHA 1910.147 |
| Return to service | Startup injury | All clear, own-lock removal, controlled restart | OSHA 1910.147(e) |
Lockout throughout the alignment
The defining control in a Machinery Alignment JHA is maintaining lockout throughout the alignment, because the millwright works in close contact with the coupling and rotating parts and an unexpected start would be catastrophic. The machine and its driver are locked out and verified at zero energy before any alignment work begins, and they stay locked out through the entire process — including when shafts are rotated by hand for measurements, which is done with the machine locked out and hands clear of pinch points. Each worker applies their own lock. A JHA built on lockout maintained throughout the alignment, with stored energy released and pinch points controlled, addresses the unexpected-startup hazard that makes alignment work dangerous despite its precision, low-energy appearance.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, machinery alignment is precision work that looks low-risk — a millwright with dial indicators or a laser tool making fine adjustments — but the hazard is real and specific: the machine starting while the millwright's hands are at the coupling. An unexpected start during alignment catches the worker in the rotating equipment, and the consequences are severe. The control is lockout/tagout maintained throughout the alignment, verified at zero energy before any contact, with the millwright's own lock on the isolation. The machine stays locked out for the entire job, including when shafts are turned by hand to take readings. The mistake that causes injuries is treating alignment as a quick adjustment not worth a full lockout — and that is exactly when the machine starts.
The pinch and crush hazards are the other constant. Aligning a machine means jacking it, shimming it, and moving it in fine increments, plus handling the coupling and rotating shafts — all pinch points for hands and fingers. On the projects I have run, the controls are using jacking and adjustment tools rather than fingers, keeping hands clear of the coupling, and controlled movements during the adjustments. The stored energy in the drivetrain and connected systems can also move the machine, so it is released or restrained before the work. The JHA that maintains lockout throughout the alignment and controls the pinch points is the one that keeps the precision work from becoming an entanglement injury.
The bottom line
A Machinery Alignment JHA names the stored-energy, the rotating-equipment, and the pinch hazards with specific controls — lockout/tagout maintained throughout the alignment with verified zero energy, stored energy released, and pinch-point discipline during jacking, shimming, and shaft rotation. Alignment looks low-risk but puts the millwright in close contact with machinery that must not start. The JHA built on lockout throughout the work is the one that protects the millwright.
Frequently asked questions
Why must machinery be locked out during alignment?
Alignment puts the millwright in close contact with the coupling, shafts, and rotating parts, and an unexpected start would catch the worker in the rotating equipment with severe consequences. Lockout/tagout maintained throughout the alignment, verified at zero energy before any contact, ensures the machine cannot start while the work is done.
Can shafts be rotated by hand during alignment?
Yes, but only with the machine locked out and the worker's hands clear of pinch points. Rotating shafts by hand to take alignment readings is done with the machine fully de-energized and locked out, never with the machine capable of starting.
What pinch hazards arise in alignment work?
Jacking, shimming, and moving the machine in fine increments, plus handling the coupling and rotating shafts, all create pinch and crush points for hands and fingers. Controls are using jacking and adjustment tools rather than fingers, keeping hands clear of the coupling, and controlled, communicated movements during adjustments.
Is stored energy a concern in machinery alignment?
Yes. The drivetrain and connected systems can store energy — rotational inertia, spring tension, hydraulic and pneumatic pressure, and connected process energy — that can move the machine or its components. This stored energy is released or restrained before alignment, with components blocked and connected-system pressure relieved.
Related JHAs
- Lockout Tagout (LOTO) JHA — the energy-isolation foundation
- Industrial Equipment Installation JHA — installing the equipment being aligned
- Equipment Commissioning JHA — commissioning after alignment
- Mechanical Pipe Installation JHA — connected piping and isolation
Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.