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Machine Guarding - St. Louis Chapter


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									Colt Equipment Inc.
St Louis Missouri

314 220 9799

Machine Safety Guidelines.

Best safety practice vs. compliance, and safety.
A machine/system can be safe, but noncompliant. It can be compliant, and not safe. Best safety
practice, includes the highest form of safety that is compliant.

General duty clause.
The employer shall provide a work place that is safe, and free from any hazards.
General machine guarding.
One or more methods of machine guarding shall be provided to protect the operator and all other
people in the machine area from hazards such as those created by point of operation, in going nip
points, rotating/flying parts, flying chips and sparks etc.
Examples of recognized safeguarding methods include properly designed and applied barrier
guards, two hand tripping devices, two hand controls, electronic safety devices; such as light
curtains, radio-frequency devices, laser detectors and other devices. As new technology emerges,
so have additional safeguarding methods. Make sure the safeguard you choose is complete and
Any and all safeguards shall not create a hazard.

Mechanical power transmission apparatus.
Flywheels, shafts, gears, pulleys, sprockets, and rotating members etc. shall be completely
enclosed up to 7 feet from the floor or any working platform. ANSI standards require 8 feet, and
other standards require 9 feet.

Lockout tag out. (Not limited to).
Mechanical, pneumatic, chemical, heat, gravitational, explosive, electrical, point of operation,
etc. hazards, should be at a zero energy state.
Proper components/procedures should be used to accomplish this state quickly and safely;
someone may have to be extracted from the machine. Rapid and safe extraction could save a life
or limb.
Required when:                            1
When removing or bypassing a safeguard or other safety device is required and/or when any
person or body parts are required to be in any potential danger zone.
When the equipment is being maintained or adjusted or repaired.
Normal periodic adjustments do not require lockout tag out, if appropriate measures have been
taken to eliminate any hazards during the adjustments.

CFR 1910.217 mechanical power presses
Provides initial detailed guidelines/standards for machine safeguarding.
Safeguarding system means all components, not just electrical. All components/systems shall
include, performance monitoring, self checking, control reliability, dual or triple redundancy at
minimum and always fail to the safe condition.

Disconnect capable being locked only in the off condition should be present, properly identified,
and accessible.
A motor starter, protected from restart hazard, should be used on all motors. Magnetic motor
starters of proper design can accomplish this. Appropriate guarded and identified start/ stop
buttons are to be used.
All buttons and switches shall be appropriately labeled. All selector switches must be capable of
supervision (key lock, key removed, password protected).
Emergency stop buttons shall comply with NFPA 79.
Should include a yellow background, manual reset, an unguarded red mushroom plunger, and
appropriately marked. Manual reset, can add a higher level of communication/safety when used
110 volts or less shall be supplied to all operator controls, obtained from a transformer with an
isolated secondary.
Appropriate grounding and indication, must be provided for protection from shocks, and
unintended operation.

Air and hydraulic machine control systems.
Pneumatic/hydraulic controlled equipment should have appropriate filtration, regulation, and
All control devices shall be properly identified and must be capable of supervision.

The system shall be free from leaks.

Properly adjusted pressure switches must be used where required for safe operation.

Appropriate redundant self-monitoring safety valves must be used to ensure safety, by matching
and match the integrity level of the electrical system and components.
All pressure vessels must meet ASME standards and have appropriate certification/identification,
and up to date inspections.
All pneumatic and hydraulic equipment shall be designed to operate within the rated capacity of
all the components, including the plumbing of the system.
Lock out valves shall safely remove any potential energy quickly. Prevent startup hazards.

Point of operation.
Point of operation is the area on the machine where the work is actually being performed upon
the material being processed. Dangers exists in many cases in other areas in addition to the point
of operation, these also must be properly safeguarded.
The point of operation of machines whose operation exposes persons to injury shall be guarded.
The guarding device shall be in conformity with any standards therefore, (ANSI standards,
national electric code, national fire protection association etc.) or in the absence of applicable
standards shall be so designed and constructed as to prevent anyone from having any part of their
body in the danger zone during the operating cycle.


Point of operation barrier guards shall prevent entry to the hazard.

This includes reaching/entering over, under, around, or through the safeguard.

Barrier guard openings shall conform to table 0 - 10, at maximum. (The minimum openings are different
to meet ANSI Standards.)

The guard shall not create a hazard, no sharp edges, and no hazards with any other moving parts.
The guard shall utilize fasteners not readily removable by an operator.

The guard shall facilitate its own inspection.

The guard shall offer maximum visibility to accomplish the task.

The guard must be mechanically interlocked. Electrically interlocked only if applicable.

Guards shall be affixed to the machine where possible and secured elsewhere if for any reason
attachment to the machine is not possible. The guard itself shall be such that it does not create
any additional hazards with the machine or any other device.
Types of guards.
Fixed guards
Adjustable guards
Interlocked guards, mechanical/electrical.
Gate guards type A and B
Perimeter guards, pass through protection.

Devices used as a safeguard.
Devices can be an option for point of operation safeguarding. All other potentially hazardous
areas must be safeguarded also.
Devices shall protect by preventing and/or stopping the machine if any part of anyone is
inadvertently placed in the point of operation/danger zones, or preventing any part of anyone
entering into the point of operation/danger zones, or withdrawing safely any part of anyone if
inadvertently located in the point of operation/danger zones, prior to or during the operation.
Sweep devices are not acceptable.

Examples of safeguarding alternatives.
Two hand control, requiring concurrent pressure of both hands on properly located control
buttons , throughout the danger cycle. The buttons must be placed at the proper safe distance,
based on the machine stopping time, using the appropriate stop time formula, and located in a
fixed position, that are protected from unintentional actuation. These systems only protect the
operator. The system must be redundant and self checking. The level of protection must be
verified as many systems/components only have a low level of reliability.
Each operator will require a complete operator station.
OSHA uses the formula 63 inches per second, hand speed constant, times the stopping time in
seconds. Additional considerations are component response time, and system response time.
Safety distance, appropriate interface, control reliability, and brake monitoring must be used if
best safety practice is the goal. Control reliability should provide protection from
unintended/improper operation of the machine, and also prohibit further operation until the
system has been properly repaired.
All actuating devices shall be protected from accidental actuation.
Examples, palm button guards and appropriate placement, and appropriately shielded foot
switches that are enclosed both top and sides, with front flap or kick plate.

Other safeguarding devices examples (restrictions apply)

Light curtains, with appropriate interface, control reliability, and safety distance. Appropriately
sized, no pass-through, proper distance, and all components of system control reliability.
Laser systems
Two hand trip.
Although radio-frequency devices are not recommended, there are applications were these can be
Gate guards. Both type A, and type B.
Guards and/or appropriate covers shall be used to protect all areas of entry to the point of
operation and other hazardous areas not protected by devices.
Additional protective devices can be utilized where applicable, but are not to be construed as
Some examples:
Pressure sensitive mats, awareness barriers properly interfaced and identified, signs, electrical
emergency stop pull cords, railings, perimeter guarding with appropriate latch reset interfaced to
the control. Hand feeding tools are not to be used in place of a safeguard. Appropriate PPE.
Work area, appropriate lighting, appropriate ventilation, appropriate floor condition, and any
other housekeeping situation that could cause a hazard, including slip/fall, devices hanging too

The ANSI standards now infer that the manufacturer of new equipment/components has the
responsibility to provide compliant, and safe products. (Do not assume this is always the
case).This could be specified as a condition of acceptance, when purchasing equipment. It is still
the employers responsibility to make sure the machine is safe, prior to use.

The development of a self-auditing safety checklist for each piece of equipment or
operation in your facility could be useful in reducing negative incidents. These can increase
productivity, reduce down time, and increase profitability.

    A risk assessment of all hazardous tasks should be performed and documented.

Examples of some of the things to be provided on the checklist are as follows.

    1. Are operation manuals up-to-date, followed, and reviewed on a regular basis?

    2. Are service manuals up-to-date, followed, and reviewed on a regular basis?

    3. Are training manuals/programs up to date?

    4. Are you taking appropriate measures to restrict/protect visitors and intruders?

    5. Are there appropriate lock out, tag out training/procedures/systems and equipment in place?
       These are not limited to just locking out the energy. It should also include safe positive release
       of any potential and/or stored energy. The LOTO system shall not create potential hazards upon
       start up. Remember someone may have to be extracted quickly from a hazard; this must be
       done safely.

    6. Are appropriate equipment/process inspections and preventive maintenance being performed
       on a regular basis?

    7. Has adequate protection been provided from chips, sparks, fire, flying parts, dust, scrap, smoke,
       and splashes?

    8. Have all point of operation/equipment hazards been properly identified and safeguarded?

    9. Have you engaged the operators?

    10. Is all equipment properly anchored?

    11. Has enough room been provided to perform the tasks safely?

    12. Is the equipment correctly sized and being used properly for the operation it is performing?

    13. Have all personnel been appropriately trained and oriented to the
        equipment/operations/safeguarding they use? Does proper documentation exist? Are the
        employees aware of all the potential hazards of their tasks, and how they are to be avoided?

14. Do all emergency stop buttons comply with NFPA 79, red mushroom button with yellow back
    ground and function properly? Are they tested regularly? Are there enough, and are they
    readily accessible?

15. Is the operation safe, and how was this determined, and by whom?

16. What, if any, changes could make it safer?

17. Is the equipment being operated within the rated capacity and being used properly for the
    operation performed?

18. Has one or more appropriate methods of safeguarding been provided to protect the employee
    and all personnel from all hazards?

19. Is the safeguarding method properly designed? Is it a recognized and complete method? Do
    control reliability, redundancy, proper interface, and appropriate self-checking exist for all
    safety components, and the complete safeguard system? Does up to date and accurate
    schematics/documentation exist?

20. Is there an appropriate, safe, testing procedure for each safeguarding component/system in
    place and regularly used?

21. Can reengineering the process reduce any risks or hazards?

22. Are appropriate signs and warnings in place?

23. Are storage facilities in good condition, and not overloaded?

24. Are aisles, stairs, railings, and exits properly marked and in good condition?

25. Are lighting, work space, floor condition, and ventilation appropriate for each task?

26. Are emergency exits adequate, marked, and functioning properly and checked regularly?

27. Have slip, trip, and fall hazards been eliminated or identified?

28. Have hazards from falling items, components, been eliminated?

29. Are hazardous materials properly stored and identified?

30. Have all hazardous conditions been properly identified and properly identified?

31. Does existing supervision insure safe procedures are being followed?
32. Are appropriate process inspections and retraining, when required, being performed on a
    regular basis?

33. Are all the equipment components and the accessories functioning properly?

34. Are all component parts operating within specification and adjusted properly?

35. Are the lubrication, filtering, and regulation systems operating properly?

36. Is the equipment operating within its rated capacity?

37. Are emergency stop buttons designed to NFPA 79 standards, unguarded red mushroom button,
    properly marked, yellow back round, and manually reset?

38. Are all controls properly labeled and capable of being appropriately supervised? (Keyed
    selectors, Passwords ) Keys must be removed, passwords protected, and only authorized and
    trained persons may have possession/access.

39. Have all start controls/buttons/switches/treadles/pedals/bars, been designed and protected
    from accidental or unintentional operation?

40. Have all unwanted restart hazards been eliminated?

41. Have all personnel been advised of proper attire, and provided with, and use, the proper PPE
    required for each task?

42. Are all methods, components, information, and systems standardized, where possible?

43. Is electrical grounding proper, and indicated?

44. Are there only 110volts or less to all operator interfaces?

45. Is the equipment free from all leaks?

46. Are regular and periodic inspections being performed to assure all components, accessories, and
    safe guards are in good/safe operating condition and adjustment? Are they being performed by
    competent personnel? Are appropriate records being kept?

47. Has the equipment been modified? Has the modification been documented? Are the safeguards
    still appropriate? Is retraining required?

48. Are appropriate emergency first response procedures in place, and drills conducted regularly.

49. Do not assume, verify. If in doubt ask first.
   50. Use common sense. When in doubt, check it out.

The employer shall provide a workplace free from recognized hazards.
Awareness training, operator training and maintenance, are required.
For example a kitchen stove has no signs or guards, yet we know not to touch. But machines do
not have the same reputation; one reason is their operations are unfamiliar to most people.

Examples of some items that should be included in your operator-training program.
Instructions to operator shall include but not be limited to;
   1.    Regular operation of the machine.
   2.    Setup/threading/preparation for regular operation of the machine.
   3.    Clearing jams or upset conditions.
   4.    Making running adjustments while the machine is operating.
   5.    Cleaning of the machine.
   6.    Oiling or greasing of the machine or machine parts.
   7.    Scheduled/unscheduled maintenance.
   8.    Lockout/tagout.
   9.    Complete task description. What is the operator to do to safely perform the tasks?
   10.   Control functions, clear and precise operating instructions and procedures.
   11.   Awareness of hazards associated with each task.
   12.   Safe feeding and retrieval methods, and scrap handling.
   13.   Safeguarding method. How to safely function test the system, and what is the required
         frequency of testing.
   14.   Near miss/incidents/accidents should be reported and investigated.
   15.   What to do in case of an accident should be clearly explained.
   16.   What are the procedures if unauthorized persons enter into your work area.
   17.   What is proper attire for the job?
   18.   Communication is a must between management, shifts/trades, and all personnel.
   19.   What are the necessary items to complete the job safely are they available and properly
   20.   Machine running status. Do I turn it off or is it safe to let it run unattended, and how long is the
         interval it can be left running safely unattended.
   21.   Inspections prior to starting a task.

What are the appropriate inspections, when are they to be performed, and by whom.
   1. Inspections: see law/standards also.
   2. Daily/ shift /operator/ change. This is an ongoing process; any abnormality should be
      appropriately dealt with and reported immediately. Then appropriately inspected, prior to
      returning to service.
   3. Follow manufacturers recommendations.
   4. Weekly.
   5. Regular and periodic. (Follow a standardized inspection of the equipment, its components,
      accessories, and the safeguarding method, in addition to following all manufacturers
      recommendations, inspections and adjustments) In addition all modifications must be in
      accordance with best safety practice, must be properly documented, and in the case that the
      modification changes the operation, changes must be made to the operation/service manuals,
      safeguarding system, in addition to changes in training and instructions for safe operation.
   6. Documentation requirements, should include the machine identifier, inspector name, title,
      badge/clock number, date, and time.
   7. You must use a qualified/competent inspector and ensure ongoing training.

When reviewing a piece of equipment for safety, ask yourself the question, would I allow my 18-
year-old child to operate this equipment with the training and safeguarding that has been
If you have questions, please feel free to contact David Bierman at
314-220- 9799
or tecknodave@cs.com.


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