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Safeguarding, Machine Guards - Table of Contents - links to content on this page

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click on the  underlined  squares  to link to the subjects ?  Our Work with Safeguarding, and its involvement in Our Forensic Engineering Work ?  Our Forensic Engineering Work - number of ? Cases  ? Reports  ? Affidavits  ? Testimonies   ?  Safeguarding Discussed ?  Safeguarding characterized by Issues ?  Safeguarding characterized by Type ?  Experience & Qualifications ?  Our Typical Work Activities & Products ?  Presentation of Results of Work ?  Geographic Area available for Work

?  Barrier Guards ?  Barrier Guards with Instrumentation ?  Safeguarding and Instrumentation ?  Safeguarding and Point of Operation

?  Contact Us by Phone, Mail or Email     ?  Consult, before and after assignment ?  Fee Schedule availability ?  Curriculum Vitae and additional Qualifications ?  Links to Other Pages (left sidebars)

E xperience and Qualifications of James D. Madden, P.E .      in regard to Safeguards and Guards, and application of Safeguarding

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Combined,  Engineering and Normal Psychology  are the scientific bases of  Human Factors  and the related studies of the human-machine interface, human-facility interface, and responses to hazards, which comprise a significant part of the foundation for  Safety Design  and  Safety Design Analysis.  Human Factors and Safety Design are the bases for the requirements for  Safeguards  as well as Warnings. James D. Madden, P.E. has specific education in Engineering and Normal Psychology, as follows:  

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as part of the Bachelors and Masters degrees in Engineering, he took extensive  coursework in Engineering

? ? during 17 years in industrial operations and engineering design specified  Safeguards  and Warnings as part of the engineering design of equipment, systems and facilities, with analysis of Safeguards and Warnings as part of safety assurance ? as a forensic engineer for over 30 years, routinely analyze  Safeguards  (physical guards, light curtains, dual operating buttons, safety instrumentation, etc.) and  Warnings , and the requirements for  Safeguards  and  Warnings , often analyzing to determine whether there is a need for  Safeguards  and/or  Warnings,  and to determine whether  Safeguards  and/or  Warnings  which are present met the needs for safety, and are the  correct choice for safety . ? during 17 years working in industrial operations and design engineering, made extensive use of  Human Factors  and  Safety Design , the bases for  Safeguards  and Safeguarding, as an integral part of engineering design, including acquiring personal knowledge of the human-machine and human-facility interfaces while working in industrial operations ?

as a forensic engineer for over 30 years, routinely use  Human Factors  and  Safety Design  principles, the bases for  Safeguards , in engineering analysis of accidents, and equipment and facilities involved in accidents

? during 17 years as a design engineer and for over 30 years in forensic engineering, have made extensive use of  Codes and Standards  and Recommended Practices, including interpretation, inclusive of requirements for  Safeguards  and Warnings ? earned  2 Engineering degrees , Bachelor of Science and Master of Engineering, and took additional credit coursework post-degree, taking coursework in physics, chemistry, mathematics, engineering mechanics, mechanical engineering, chemical engineering and normal psychology ? earned the  Professional Engineers license  (P.E.) by taking the National Council of Engineering Examiners' examination in Fundamentals of Engineering and the  Mechanical Engineering  and  Chemical Engineering  sections of the National Council of Engineering Examiners' (NCEE) examination in Principles and Practices of Engineering ? designated a  Diplomate Forensic Engineer  by the National Academy of Forensic Engineers in accordance with the standards of the Council of Engineering and Scientific Specialty Boards (CESB) ? at the start of forensic work, completed  refresher and additional post-degree college credit coursework  and continuing education coursework in mechanical engineering, metallurgy and materials

?  attended  engineering seminars  presented by the National Academy of Forensic Engineers

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regularly attend additional  technical courses and seminars  each year to meet the requirements for continuing engineering education for the Professional Engineer's license ?  over  40 years of engineering experience , with:  ?  17 years experience in  industrial operations, engineering design  and  construction assistance  ?  30 years experience in  forensic engineering , including:   ?  testifying in  over 90 depositions  and  over 75 trials ?  issuing  over 600 reports  and  over 60 affidavits ?  working on  over 1000 cases See more about qualifications of  James D. Madden, P.E. on the  Qualifications Page . See details of the forensic work throughout this website, and a summary on the  Employment Page . See details of the pre-forensic work on the  Employment Page  and the  Engineering Design Page .

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S afeguards, Safeguarding, including  physical guards, light curtains,     dual operating buttons, safety instrumentation, etc.    ?  other names for safeguards include machine guards, guards, etc.

Safeguarding and  Safeguards  are based on knowledge from  Human Factors  and are a  requirement in  Safety Design . Safeguards are included in many generally accepted  Codes, Standards and Recommended Practices .  Warnings  and Safeguards are used in prescribed manners related to the safety of the use of one or the other in particular circumstances. These subject areas are all closely related. The information that follows is not intended to be exhaustive, Safeguarding is a large issue with many publications covering various aspects of the subject. The coverage below is intended to introduce the subject. The organization of the materials below is one way to look at the subject. The choice to use Safeguards, and the specifics of any particular Safeguard requires engineering analysis of many factors in the areas of Engineering Design, Human Factors and Safety Design.

Relationship of Safeguards and Safeguarding    to Human Factors, Safety Design, Warnings, and Codes and Standards

Safeguarding and  Safeguards  in design are based on the knowledge from  Human Factors  and are an integral part of  Safety Design . There is a long history of use of safeguards, and many safeguards that are routinely used have a proven effective history in use in various particular circumstances. Safeguards are enshrined in many generally accepted  Codes, Standards and Recommended Practices .  The choice of safeguards as the design solution to safety hazards is based on the principles of the  Safety Design  and particularly the  Safety Design Hierarchy , which is the accepted system for design of safe equipment, systems, products and facilities. The Safety Design Hierarchy requires that  safety hazards  be  designed out  of the equipment, products and facilities wherever and whenever possible. Only if the hazards cannot be designed out, are safeguards used to protect against the hazards. The Safety Design Hierarchy also requires that  Warnings not  be used in place of Safeguards if Safeguards will protect against the hazard. If Safeguards will protect against the hazards,  Warnings are used to complement safeguards when this adds to the safety of the installation where safeguards are being used to protect from hazards. Safeguards and Warnings are  not  interchangeable. 

For more information see  >>                Safeguards and Safeguarding, characterized by issues

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? Safeguards  can be considered to cover at least the following  issues :

• the  point-of-operation  for industrial equipment, commercial equipment and consumer products, such as the point of operation between the dies in a stamping press, where the metal part is stamped into a shape, under conditions where the metal part must be inserted in between the dies repetitively by an operator during the operation

• non-point-of-operation hazards  for industrial equipment, commercial equipment and consumer products such as moving chains on sprockets (an example of an in-running nip point)

• intermittent hazards to users  particularly for equipment passively used by the public, such as the doors on an elevator, where the location of the passenger cage (the elevator) determines whether it is safe for the doors to the elevator shaft to open 

 Safeguards and Safeguarding, characterized by types

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? Safeguards  can be considered to consist of the following  types :

• physical guards  or barrier guards which literally prevent access to the hazard, at least during operations, often accompanied by safety instrumentation to sense the unauthorized disabling of the guard, and to stop or alter the operation to prevent access to the hazard, usually disruptively to the operation

• physical guards coupled with safety instrumentation for operations  whose physical guards are intended to be circumvented at will, but preferably infrequently, during operation to alter or stop the equipment operation to eliminate the hazard when the physical guard is circumvented, such as a door to the hazard that can be opened at will while the equipment is operating - such an arrangement is often at least somewhat disruptive to operations when the safety instrumentation alters or stops the operation of the equipment, so its use is usually discouraged

• safety instrumentation  which prevents access to the hazard when it is a hazard

• safeguarding devices  that allow access to the normally hazardous area, and simultaneously prevent the hazard from being effective as a hazard to the operator and others with access at that time - such devices are usually closely integrated into the equipment operation and are not disruptive, or minimally disruptive, to the planned operations. although they may have a major impact on productions rates

 Physical Guards, Barrier Guards

P hysical guards , barrier guards, are often effectively fencing or grating. They are commonly used to prevent access to hazards which require no access for operation of the equipment. They are often accompanied by safety instrumentation that will stop operations if the barrier guard is removed or altered enough to expose the hazard. This alteration or removal is not intended to be a part of normal operations, even occasionally.

? Examples of hazards that may be effectively protected against by  physical guards , barrier guards, usually without operational effects, include:

• in running nip points

• rotating components  such as flywheels, gears and shafts

• pinch points  between moving and stationary components of machinery

 Physical Guards, Barrier Guards,        coupled with safety instrumentation for operations

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Physical guards coupled with safety instrumentation for operations  whose physical guards are intended to be circumvented at will, but preferably infrequently, can be used where operating problems may require that the operation be altered to resolve the operating problem, and part of that alteration involves accessing equipment locations which are hazardous in normal operation.  A door to such a hazardous location is an example of this type of safeguard. This door could be for access by a hand, such as on some lathes, or a whole person, such as with some plastics processing equipment. Safety instrumentation associated with  physical guards coupled with safety instrumentation for operations  is designed to be the least disruptive to the operations as is feasible, while still safe, as opposed to safety instrumentation associated with physical guards to prevent persons disabling the guards and continuing operation with the hazard exposed. Such instrumentation to prevent disabling the guards can be very disruptive to operations.

 Safety instrumentation which prevents access to the hazard

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Safety instrumentation which prevents access to the hazard  when it is a hazard is most often used in conjunction with equipment that has varying times during its use when it would be hazardous to a user, and other times when its use would not be hazardous to a user. An example of that would be the doors to an elevator shaft. When the elevator occupant cage is properly located at the floor, opening the door and stepping through the doorway into the elevator shaft is safe. When the elevator occupant cage is located at a considerable distance from the floor, opening and stepping through the door would be very hazardous. When the elevator occupant cage is located several inches above or below the floor, opening and stepping through the door could lead to a serious fall. Such instrumentation to be true safety instrumentation must be  fail-safe , which means that if there is a failure in the instrumentation, the equipment will be rendered safe, even at the cost of being non-operational, if that is the safe condition. In the case of the example elevator, the doors would not automatically open for users until the failure in the safety instrumentation was repaired.

 Safeguarding Devices, especially for use at and near the point-of-operation 

Some Safeguarding Devices are very effective for the special problem of the  point-of-operation . The point-of-operation is the location where items are being processed and worked. These safeguarding devices may allow access to a normally hazardous area, only when the area is not hazardous, or may prevent the hazard from being effective as a hazard to the operator and others when access is allowed, or may allow an operator to get close to a hazardous area without contacting the hazardous area, without using a barrier guard.  Often the operator or others must access the point-of-operation during operations. In some operations the operator may be required to access the point-of-operation repetitively many times an hour, perhaps every few seconds, even placing his hand repetitively between dies in a stamping press, for example. These safeguarding devices are intended to eliminate the hazard passively when the operator enters the point of operation (for example, with his hand), or to prevent the operator from accessing the point of operation when it is a hazard, without using a barrier guard.

? Examples of safeguarding devices that allow access to a normally hazardous area only when it is not in a hazardous condition, or create the non-hazardous condition during access, which are especially useful at the point-of-operation, include:

• presence sensing devices, such as light curtains  associated with such equipment as automated presses, and presses operated by the operator with a foot pedal, a single hand button, or any other device that leaves his hand or hands free to go into the point-of-operation when they could be injured - these devices stop movement or take whatever action is necessary to protect from the hazard when they are interrupted by a body part

• dual operating buttons,  such as dual palm buttons, useful wherever the operator alternates between accessing the point-of-operation, such as inserting a part between dies, and then must operate the next cycle of the equipment, usually creating a hazard to the operators hand(s) or other body parts during this cycle - the location of the dual operating buttons must be such that these body parts cannot be contacted by the hazard while the dual operating buttons are being actuated

• pullbacks  which literally will pull an operators hands and/or arms from the area of danger at the time that the hazard exists - these devices must be put on by the operator and properly adjusted to be effective

• restraints  which prevents a body part of the operator from entering the hazardous area, useful when the operator must get close to the point-of-operation during the operation, but does not have to get into the hazardous area of the point of operation, but cannot be isolated from the point of operation by a barrier guard - these devices must be put on by the operator and properly adjusted to be effective

• an automatically controlled moving barrier(s)  which can be used when certain physical areas are hazardous at certain times, and not at other times. and which allows access to the normally hazardous area only when it is not hazardous to the operator

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O ur Typical Work Activities and Products, when warranted by the case Our work investigating, analyzing and reconstructing accidents, and presenting the results, may include any  or all of the following, depending on the needs of the case:  ? inspection of the accident site , such as a roadway, outdoor facilities, building or industrial facilities inspection of the involved equipment , in current condition, including in damaged condition (such as crashed vehicles); and when available for operation, during operation (such as industrial equipment) ? ? photography  and/or  video  of the accident site and involved equipment ? interviewing witnesses  (often during the inspection of the accident site, product and/or equipment) review and study  of case documents, evidence and applicable codes, standards, regulations and recommended practices ? ? testing  accident items and exemplar items (such as consumer products) drawings, calculations, graphical analyses, computer analyses , etc. as required to analyze and reconstruct the accident, and to present the engineering analysis and reconstruction ? ?  written  reports  and  affidavits , and  exhibits coordinating or interfacing with others while they are preparing  specialized exhibits  such as video animations and videos of demonstrations ? ? testimony in deposition ,  trial  and  arbitration

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P resentation of results of our work We present the results of our investigations, engineering analyses and reconstructions in  the client's choice of any, or all, of the following:  ? verbal reports,  by telephone or in face-to-face conferences ?  written  reports  and  affidavits ? deposition testimony,  including video deposition ? trial testimony  and arbitration testimony

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F orensic Engineering Work by Senior Forensic Engineer James D. Madden, P.E.  James D. Madden, P.E., while performing  Forensic Engineering  work full-time for over  the last  30 years , for both plaintiff and defendant, has to date: ?  completed  over 1000 cases ?  written and issued  over 600 reports           ?  written and issued  over 60 affidavits ?  testified in  over 75 trials                  ?  testified in  over 90 depositions For more on qualifications see the  Qualifications Page .  <<< Click on the underlined text

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C ontact information

For mailing  address ,  phone ,  fax  and  email  address click a button below the Fee Schedule section.

F ee Schedule

Contact us by phone, fax, mail or email for a copy of the Fee Schedule for charges for engineering and consulting services and testimony.  Click a button below for contact information.

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G eographic Area of Practice - North America 

Over the last 30 years we have regularly worked on accidents which occurred in  Ohio, Pennsylvania, Michigan, New York and nearby , including inspections of accident sites, equipment, and facilities, with reports and testimony. During these 30 years we have also worked on accidents which occurred in  other states , and equipment and facilities located in other states, with inspections of accident sites, equipment, and facilities,  from Utah and Kansas to Vermont and North Carolina,  with reports and testimony for these accidents, when applicable.

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Madden Accident Analysis &   Forensic Engineering

Madden Accident Analysis & Forensic Engineering 1700 West Market Street, Suite 318, Akron, Ohio 44313, or 8803 Brecksville Road, Suite 7-216, Cleveland, Ohio 44141 phone: 440-838-1191 or 440-832-9540, fax: 440-838-1192 email address: [email protected]

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