The Third Level of the Hierarchy: Information for Use

This entry is part 3 of 3 in the series Hierarchy of Controls

I’ve writ­ten about the Hierarchy of Controls in past posts, but I’ve focused on the ‘engin­eer­ing’ side of the con­trol equa­tion: Physical changes to machine design to elim­in­ate haz­ards, and mech­an­ic­al or elec­tric­al con­trol sys­tems that can reduce risk.

The first two levels of the Hierarchy, Elimination/​Substitution and Engineering Controls, are typ­ic­ally more chal­len­ging to apply in most people’s minds, because expert know­ledge is required. These levels are also more effect­ive in con­trolling risk than the sub­sequent levels.

The Third Level

iStock_000009386795Small - Photo of Instruction manualThe third level of the Hierarchy is ‘Information for Use’, some­times abbre­vi­ated as ‘IFU.’ This level is decept­ively simple, and is fre­quently the level people want to jump to when the oth­er con­trols seem too dif­fi­cult to imple­ment. Done well, inform­a­tion for use can make a sig­ni­fic­ant con­tri­bu­tion to risk con­trol. Unfortunately, it’s done poorly or not at all more often than it’s done well.

Information for use includes:

  • Instructions and Manuals;
  • Operator Device tags and Legend Plates;
  • HMI screens;
  • Hazard Warning signs and labels;
  • Training Materials (text, video, audio) and Training (face-​to-​face, webinars, self-​directed);
  • Sales and mar­ket­ing mater­i­als.

Information for use is needed in all the stages of the product life cycle: Transportation, Installation, Commissioning, Use, Maintenance, Service, Decommissioning and Disposal [1]. At each stage in the life cycle, the con­tent of the inform­a­tion and the present­a­tion may be dif­fer­ent. In every stage it can make a sig­ni­fic­ant con­tri­bu­tion to risk reduc­tion by com­mu­nic­at­ing the safe approach to the tasks in that stage, and the risks related to those tasks. The inform­a­tion should include the inten­ded use and the fore­see­able mis­uses of the product. This is a leg­al require­ment in the EU [2], and is a best-​practice in North America.

In this art­icle I’m going to focus on instruc­tion manu­als. If you’re inter­ested in Hazard Warnings, includ­ing signs, labels, and integ­ra­tion into manu­als and instruc­tions, watch for a future post on this top­ic.

Legal requirements and standards

In the European Union, the leg­al oblig­a­tion to provide inform­a­tion with a product is enshrined in law [2].
No North American jur­is­dic­tions make an expli­cit require­ment for instruc­tions or inform­a­tion for use in law, but many product spe­cif­ic stand­ards include require­ments for the con­tent of manu­als.

CSA Z432 [3] out­lines require­ments for con­tent in Clause 17, and in EN 60204 – 1 [7]. IEC 62079 [4], provides guid­ance on the design and present­a­tion of instruc­tions. ANSI Z535.6 [5], provides spe­cif­ic instruc­tions on inclu­sion of haz­ard warn­ings in manu­als and instruc­tions.

Training require­ments are also dis­cussed in CSA Z432 [3], Clause 18.

5% Discount on ISO and IEC Standards with code: CC2011 

In the USA, provid­ing inform­a­tion for use with a product is con­sidered to be sound ‘due dili­gence’, how­ever, provid­ing inform­a­tion on resid­ual risk is often seen by liab­il­ity law­yers as dan­ger­ous, since man­u­fac­tur­ers are provid­ing inform­a­tion, in writ­ing, that their product is not ‘per­fectly safe.’ If you’ve read any­thing I’ve writ­ten on risk assess­ment, you’ll know that there is no such state as ‘per­fectly safe.’ If a haz­ard exists, a poten­tial for harm exists, a prob­ab­il­ity can be assessed and thus risk exists, how­ever remote that risk may be. I think that this argu­ment by some liab­il­ity law­yers is fatu­ous at best.

Kenneth Ross, one of the lead­ing product liab­il­ity law­yers in the USA, dis­cusses the require­ments for warn­ings and instruc­tions in an art­icle pub­lished in 2007 [6]. In the art­icle, he explains the US require­ments:

Product sellers must provide “reas­on­able warn­ings and instruc­tions” about their products’ risks. The law dif­fer­en­ti­ates warn­ings and instruc­tions as fol­lows:

Warnings alert users and con­sumers to the exist­ence and nature of product risks so that they can pre­vent harm either by appro­pri­ate con­duct dur­ing use or con­sump­tion or by choos­ing not to use or con­sume.”

Instructions “inform per­sons how to use and con­sume products safely.”

A court has held that warn­ings, stand­ing alone, may have no prac­tic­al rel­ev­ance without instruc­tions and that instruc­tions without warn­ings may not be adequate.

Therefore, when the law talks about the “duty to warn,” it includes warn­ings on products in the form of warn­ing labels; safety inform­a­tion in instruc­tions; instruc­tions that affirm­at­ively describe how to use a product safely; and safety inform­a­tion in oth­er means of com­mu­nic­a­tion such as videos, advert­ising, cata­logs and web­sites.

The law says that a man­u­fac­turer has a duty to warn where: (1) the product is dan­ger­ous; (2) the danger is or should be known by the man­u­fac­turer; (3) the danger is present when the product is used in the usu­al and expec­ted man­ner; and (4) the danger is not obvi­ous or well known to the user.”

Read Mr. Ross’ latest art­icle on warn­ings.

This prac­tic­al and sens­ible approach is very sim­il­ar to that in the EU. Note the require­ment that “instruc­tions that affirm­at­ively describe how to use a product safely.” The  old list of “don’ts” doesn’t cut it – you must tell your user how to use the product in an affirm­at­ive way.

Second Best

So why is it that so many man­u­fac­tur­ers settle for manu­als that are barely ‘second best’? In many com­pan­ies, the doc­u­ment­a­tion func­tion is:

  • Not seen to add value to the product;
  • not under­stood to have leg­al import in lim­it­ing product liab­il­ity;
  • giv­en little effort.

The per­cep­tion seems to be that manu­als are pro­duced primar­ily to fill fil­ing cab­in­ets and that cus­tom­ers don’t use the inform­a­tion provided. This leads to manu­als that are writ­ten after-​the-​fact by engin­eers, or worse, the role of ‘tech­nic­al writer’ is seen to be an entry level pos­i­tion often filled by interns or co-​op stu­dents.

End-​user train­ing is fre­quently giv­en even less thought than the manu­als. When designed togeth­er, the manu­al will sup­port the train­ing pro­gram, and the train­ers can use the manu­al as one of the primary train­ing tools. This provides con­tinu­ity, and ensures that the train­ing pro­cess is prop­erly doc­u­mented.

iStock_000012657812Small - Techncial ManualMy exper­i­ence is that few engin­eers are excel­lent writers. There are some, no doubt. Writing manu­als takes a sound under­stand­ing of edu­ca­tion­al the­ory, includ­ing an under­stand­ing of the audi­ence to whom the mater­i­al is dir­ec­ted. The level of tech­nic­al soph­ist­ic­a­tion required for a simple house­hold product is com­pletely dif­fer­ent from that required for the tech­nic­al sup­port manu­al for an indus­tri­al weld­ing laser.
The engin­eers design­ing and integ­rat­ing an indus­tri­al sys­tem are often too close to the design of the product to be able to write effect­ively to the tar­get audi­ence. Assumptions about the level of edu­ca­tion that the user will have are often incor­rect, and key steps may be skipped because they are assumed to be ‘com­mon know­ledge.’

Quality doc­u­ment­a­tion is also a cus­tom­er ser­vice issue. Products that are well doc­u­mented require less cus­tom­er ser­vice sup­port, and when cus­tom­ers do need sup­port, they are gen­er­ally more sat­is­fied with the res­ult.

New Delivery Methods

The deliv­ery meth­ods for tech­nic­al doc­u­ments have changed con­sid­er­ably in recent years. Large, ring-​bound paper manu­als are being dis­placed by on-​line, inter­act­ive doc­u­ment­a­tion that can be accessed at the user inter­face. The use of PDF-​format manu­als has jumped, and this brings in the abil­ity to link error mes­sages gen­er­ated by the con­trol sys­tem to the sec­tions of the manu­al that related to that aspect of the sys­tem. Video and anim­a­tions can be added that provide at-​a-​glance under­stand­ing of the oper­a­tion of the machinery. WiFi net­works in indus­tri­al facil­it­ies, along with the accept­ance of mobile pad-​computing devices like the Apple iPad, mean users can have the instruc­tions where they need them, and tech­ni­cians and ser­vice per­son­nel can take the manu­al with them to the area where a prob­lem exists, and can use the doc­u­ments even in very low-​light con­di­tions.

Finding tech­nic­al writ­ing resources can be a chal­lenge, par­tic­u­larly if you are look­ing to move away from paper to elec­tron­ic doc­u­ment­a­tion. The stand­ards men­tioned in this art­icle are a good place to start.
Documentation can range from writ­ing through tech­nic­al illus­tra­tions, anim­a­tion and video pro­duc­tion. Finding indi­vidu­als who can provide you with pro­fes­sion­al ser­vices in these areas in a timely way and at a reas­on­able price is not an easy task. If you need assist­ance ran­ging from a few ques­tions that need answers to hir­ing a tech­nic­al writer, Compliance InSight Consulting can help. Contact me for more inform­a­tion!

Are your product manu­als as good as they could be? What kinds of chal­lenges have you had with get­ting them writ­ten, or used? Add your com­ments below!


5% Discount on ISO and IEC Standards with code: CC2011 

[1]    “Safety of machinery – General prin­ciples for design – Risk assess­ment and risk reduc­tion”, ISO Standard 12100, 2010

[2]    “DIRECTIVE 2006/​42/​EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 17 May 2006 on machinery, and amend­ing Directive 95/​16/​EC”, Annex 1, Clause 1.7, European Commission, 2006.

[3]    “Safeguarding of Machinery”, CSA Standard Z432, Canadian Standards Association, 2004.

[4]    “Preparation of instruc­tions – Structuring, con­tent and present­a­tion”, IEC Standard 62079, International Electrotechnical Commission, 2001.

[5]    “American National Standard For Product Safety Information in Product Manuals, Instructions, and Other Collateral Materials”, ANSI Standard Z535.6, American National Standards Institute, 2006.

[6]    K. Ross. “Danger! The Legal Duty to Warn and Instruct”, Risk Management Magazine, [web] 2007, Available: No longer avail­able.

[7]      “Safety of machinery — Electrical equip­ment of machines — Part 1: General require­ments”, CENELEC Standard EN 60204 – 1, CENELEC, 2009.

Inconsistencies in ISO 13849 – 1:2006

This entry is part 7 of 8 in the series Circuit Architectures Explored

I’ve writ­ten quite a bit recently on the top­ic of cir­cuit archi­tec­tures under ISO 13849 – 1, and one of my read­ers noticed an incon­sist­ency between the text of the stand­ard and Figure 5, the dia­gram that shows how the cat­egor­ies can span one or more Performance Levels.

ISO 13849-1 Figure 5
ISO 13849 – 1, Figure 5: Relationship between Categories, DC, MTTFd and PL

If you look at Category 2 in Figure 5, you will notice that there are TWO bands, one for DCavg LOW and one for DCavg MED. However, read­ing the text of the defin­i­tion for Category 2 gives (§6.2.5):

The dia­gnost­ic cov­er­age (DCavg) of the total SRP/​CS includ­ing fault-​detection shall be low.

This leaves some con­fu­sion, because it appears from the dia­gram that there are two options for this archi­tec­ture. This is backed up by the data in Annex K that under­lies the dia­gram.

The same con­fu­sion exists in the text describ­ing Category 3, with Figure 5 show­ing two bands, one for DCavg LOW and one for DCavg MED.

I con­tac­ted the ISO TC199 Secretariat, the people respons­ible for the con­tent of ISO 13849 – 1, and poin­ted out this appar­ent con­flict. They respon­ded that they would pass the com­ment on to the TC for res­ol­u­tion, and would con­tact me if they needed addi­tion­al inform­a­tion. As of this writ­ing, I have not heard more.

So what should you do if you are try­ing to design to this stand­ard? My advice is to fol­low Figure 5. If you can achieve a DCavg MED in your design, it is com­pletely reas­on­able to claim a high­er PL. Refer to the data in Annex K to see where your design falls once you have com­pleted the MTTFd cal­cu­la­tions.

Thanks to Richard Harris and Douglas Florence, both mem­bers of the ISO 13849 and IEC 62061 Group on LinkedIn for bring­ing this to my atten­tion!

If you are inter­ested in con­tact­ing the TC199 Secretariat, you can email the Secretary, Mr. Stephen Kennedy. More details on ISO TC199 can be found on the Technical Committee page on the ISO web Site.

EC Machinery Working Group meets

From our friends at MachineBuilding​.net.

It is now more than a year since the new Machinery Directive (2006/​42/​EC) came into force, but the situ­ation is still fairly flu­id in some respects. The EC Machinery Working Group meets reg­u­larly to dis­cuss mat­ters relat­ing to the Directive and cor­res­pond­ing stand­ards; the last meet­ing took place on 21/​22 December. According to the Stakeholder Report pub­lished in the UK by BIS (the Department for Business, Innovation & Skills), a num­ber of issues were dis­cussed, which demon­strates that the Machinery Directive is not as ‘black and white’ as might be expec­ted.

For example, EN 12635 (Industrial, com­mer­cial and gar­age doors and gates – Installation and use) is cur­rently har­mon­ised to the Machinery Directive, but the UK has raised a form­al objec­tion against this stand­ard, as it would appear that there is scope for improve­ment. Other top­ics under dis­cus­sion ranged from vari­able reach trucks, tail lifts and load­er cranes, to stave split­ters, dynamo­met­ers and ‘grey’ imports of machinery.

If you would like more inform­a­tion, cop­ies of the cur­rent and pre­vi­ous Stakeholder Reports are avail­able in PDF format from the UK Department of Business Information & Skills (BIS) web site.

Machinery Directive stake­hold­er report: February 2011 (PDF, 81 Kb)

Machinery Directive Working Group held on 1 – 2 June 2010, Brussels (PDF, 56 Kb)