Condition Based Maintenance – Monitoring Tools

Hi,

I keep getting updates on new products used in the maintenance field through various online subscriptions.

Here is a link that shows the us of Ultrasound devices in the condition based maintenance strategy. I am not trying to sell the product, but am just trying to propagate the techniques involved. Please connect to the link given below and learn more.

http://www.uesystems.com/new/applications/

KayCee

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Importance of Training the work force on Electrical Safety

Hi,

Electrical Power is used by all the staff members in a work force, at all levels.

To be safe, it is essential that every one understands the importance of basic electrical safety. For those who work on powered equipment, it is vital that they know more about electrical safety.

To achieve near zero electricity power related accidents in any organisation it is a must that layered, regular training and refresher sessions are conducted. Audit on how people comply to safety rules is also essential to measure the training effectiveness and attitudinal change brought about.

Here is a link to an article on the importance of training and audit on electrical safety.

http://www.plantservices.com/articles/2013/best-electrical-safety-practices-for-your-plant/?show=all

Regards

Kaycee

Electrical Systems: The history of electrical safety

Hi all,

Making “Safety at work” a religion will help save many lives, will reduce accidents and injuries, improve individual productivity, business reputation, employee loyalty and the overall bottom line of any business.

Every aspect of work needs to be made safe, but one of the most hazardous and common place accident prone area is people working on electrical installations.

What is visible is generally comprehended and people become aware of the danger and take care. An arc flash is a hidden danger and can strike at will from any of the closed and secure switchgear cabinets.

I found this very infomative article on the history of electrical safety and the evolution of OSHA standards regarding the same in the Plant Services online magazine. Please click on the link to read.

Electrical Systems: The history of electrical safety.

Safety is everybody’s business. The Managers have the additional responsibility of ensuring that his team is fully aware of the safety requirements and adhere to all the regulations in letter and spirit. Thisis part of the team building exercises and training.

Kaycee

Look, Listen and Feel – in Condition Based Maintenance

Hi all,

With due respect to all the gadget geeks and proponents of high-tech equipment to carry out condition based maintenance; the age-old classic forms of observations as indicated below are still valid in the field of condition based maintenance; probably as the first information report function.

Look ………. Listen ………. Feel!

The basics of good maintenance start from the careful, systematic, periodic inspection of equipment and system elements – the first step. Recording of observations is the second step. Analysis of the observations by a maintenance team leader would be the third step.

Essential Safety Precautions for the Look / Listen / Feel Work

Wear all essential personal protection equipment prescribed for each installation. Examples – for high noise areas, ear defenders are a must; eye protection is essential where high dust, fumes, vapours, flying sparks etc conditions exist. Safety shoes are required to be worn in all conditions. Rubber soled shoes with fibre re-inforced toes are to be worn while working on electrical panels and equipment.

Individuals must be deployed for such jobs only after successfully being certified in safety aspects and equipment skills.

Visual inspectionLook

Before starting an equipment or systems: Good maintenance practices exhort users and maintainers to do a full visual inspection of equipment and systems before they are put into use, each time and every time. Such a visual inspection could reveal tell-tale oil or lubricant leaks, discolouration of protective paint due to overheating, corrosion spots, damaged parts, missing elements such as belt / chain guards, dust and debris collection, physical obstruction etc. Clearing all the abnormalities before putting the equipment or systems to use will increase their reliability.

Identifying “Lock Out Tag Out (LOTO)” Conditions: Visual inspection of control (mechanical / electrical) elements will help in identifying the LOTO conditions. In case the equipment is tagged out or locked out; operations are not possible till that condition is cleared by the person who locked it or tagged it.

Running equipment or systems: Periodic visual inspection of equipment or systems while in operation is also essential.

  • This could be done manually by visiting each equipment, looking at the equipment as a whole, checking the relevant critical parameters from their respective meters, checking for abnormal visual vibrations, checking for visible leaks, checking for overheating, checking for spray or flow quality / quantity (example – cooling tower water nozzles),
  • Alternatively, for large installations with high automation and central controls, the visual inspection could be through CCTV cameras, monitoring of parameters through data loggers, online vibration measurement, etc.

ListenListen

This is mostly applicable to equipment with rotating elements (motor driven pumps, fans, compressors etc).

Loose components or sub elements on the equipment may cause audible rattling noise. If left unattended, these could lead to consequential damages.

This technique needs some skill and long involvement of the operator or maintainer with the equipment under his or her charge. The operator / maintainer need to develop a skill on “what to listen to” and on how to identify “wrong noise”. This comes from experience.

On the long run, an operator will be able to make out the change in noise at a motor bearing or a fan air cutting noise due to blade damage. At this point it may be subjective, but a requisition for more precision measurements could be initiated before a major damage occurs.

A long stem screw driver or a simple mechanical stethoscope made out of thin, rigid, long copper tube with a small brass ear cup (a simple washer would do) attached to it could be used as an effective listening aid.

Please be wary that very noisy equipment should not be listened to with unprotected ears and the listening aids mentioned above. Prolonged exposure to loud noise could lead to permanent hearing loss progressively.

FeelFeel

The “Feel” factor is an equally important tool in condition monitoring. One needs to be a bit cautious on this aspect since many of the running equipment could have hot surfaces and may not be directly touchable, without causing harm. On the same lines, there could be system elements that run very cold and touching them with unprotected hands could cause cold burns or skin peeling. The Maintenance managers need to decide on what can be touched to feel.

Safety is very important here since the “Feel” actions are generally done on running equipment. Care should be taken to avoid putting the palm very close to moving parts

The “Feel” gives you some idea on the difference in temperature, non-visual vibration level changes, flow quality (turbulent or otherwise), presence or absence of flow, presence or absence of a liquid in a container or pipe, heaviness or lightness of an item, rigidity or flexibility of an item, speed / velocity changes etc. “Feel” is  through the skin and the palm is the best suited body part for the purpose.

Combination of Look, Listen and Feel

Practised together, the above combination provides a very thorough basic condition monitoring technique. experience on the field and safe working habits bring in a slew of benefits in OEE and reliability.

One thing good about this is that it is a value addition to the service rather than eating into a lean and mean budget allocation.

The observations from the above technique could lead to more precise measurements of temperature gradient using a thermal imaging camera, vibration monitoring using hand-held equipment etc.

Visual Factory

Appropriate signage placed at strategic locations could make the Look, Listen and Feel inspection systematic.

Place pictures of eyes where visual inspection needs to be done. Pictures of ears and palm would indicate the listen and feel activities.

Added to these, station markings arrows could be marked on the ground indicating which positions the operator or maintainer should take and direction to face the equipment to make an observation.

Further arrow markings to indicate the direction to be taken while making observations could be done to optimise effort and time taken for observations.

Tail Piece

Smell The human nose can discriminate difference in smells. For example, the smell of overheated or burning oil in a diesel engine has a very recognizable odour.

Heated or burning electric insulation also has a very distinct odour.

The smell of a burning flourescent lamp choke is very discernible.

Smell of a dead rodent in a ventilation duct can be very disturbing.

So, the nose also can be a very reliable sensory organ in equipment / system condition monitoring.

Comments are solicited on my thoughts expressed in this post.

KayCee

Safety Matters, While Working in Confined Spaces Part 3

This article has been written out of personal and institutional experiences and should not be taken as a formal guideline for working in confined spaces. Please refer to relevant safety manuals before undertaking such work.

This is the third and final part of this series.

Part 1 is an introduction to “Confined Spaces”.

Part 2 contains thoughts on “Testing the atmosphere within confined spaces”, “Isolating the confined spaces”, “Other likely hazards within confined spaces”, “Personal protection gear”, “Support team” and “Training” aspects.

A link to the check list to ascertain safety for entering confined spaces is given below. Please go through. You are welcome to copy, download and use the same if you want to.

Confined Space Entry Safety Checklist

“Work Safe, Be Safe, Live Safe…….Live and Let Live”

Safety Matters, While Working in Confined Spaces Part 2

This article has been written out of personal and institutional experiences and should not be taken as a formal guideline for working in confined spaces. Please refer to relevant safety manuals before undertaking such work.

This is the second part of this series. Part 1 is an introduction to “Confined Spaces”.

Testing the Atmosphere

Never trust your senses to determine the presence or absence of gases in a confined space. Some of the toxic gases and vapours are colourless and odourless, hence you can neither see or smell them. You cannot determine the level of Oxygen present also by your nose.

The prevalent atmosphere should be tested using properly calibrated instruments / miner’s safety lamp etc before “Safe to work Certificates” are issued.

  • Some of the gases or vapours are heavier than air and tend to settle to the bottom of a confined space – Example, Hydrogen Sulphide or Steam which do not sustain life.
  • Some for the gases are lighter than air and will rise to the top of a confined space – Example, Methane, which does not sustain life.
  • Some of the gases may have the same density as air and will occupy the rest of the space – Example, Carbon Monoxide which does not sustain life.

It is essential that all the areas in a confined space are tested for presence of gases and absence of Oxygen. In both the cases, the area is to be ventilated using external air sources (Supply or Exhaust or Supply and Exhaust). The exhaust gases should be let out to well ventilated spaces, preferably open air.

If steam or inert gases have been injected into a confined space, the space needs to be ventilated before effecting personnel entry since both steam and inert gases are non-life sustaining. For example, some of the aviation turbine fuel tanks are automatically filled with Nitrogen as the fuel level falls.

Steam will increase the temperature of the space and the space is to be allowed to cool before allowing people to enter and work.

Care should be taken so that no electrical spark is introduced into the confined space. The motor drive for the supply / exhaust fans and their controls should be outside the confined space.

After ventilating for about 24 hours, the confined space is to be re-tested for presence of hazardous gases and presence of life-sustaining levels of Oxygen. Personnel should be allowed to enter the compartment only when the test results are satisfactory.

Even after the atmospheric tests conducted in a confined space is deemed satisfactory, the condition can reverse due to the nature of work carried out within the space.

  • For example, if a metallic tank is chipped and cleaned initially and paint application has been done, the paint fumes are both hazardous and flammable.

  • Another example is hot work such as cutting / brazing inside a confined space will reduce the Oxygen level and leave hazardous gases within.

In all cases, periodic monitoring is essential to ensure that confined spaces are safe to work within. This is applicable for carrying out hot work onto the confined space walls from outside as well. For example, if hot work is to be carried out on to the metal sides of a confined fuel tank, the tank needs to be inspected and cleared as “Safe to work” periodically.

Isolation of the Confined Spaces

The confined space where work is to be carried out internally and externally should be isolated from all energy sources through “Lock Out Tag Out “ processes as follows:

  • All electric circuits should be switched off and the incoming switch locked.

  • All other energy such as hydraulic and pneumatic air supplies should be bled till empty and the supply valves are to be shut and locked.

  • All mechanical drives such as belt or chain drives should be disconnected and stowed away.

  • All mechanical moving parts within a confined space should be secured safely.

  • The entry manhole cover should be opened and secured safely in the open position to avoid accidental closing.

Other Hazards

Confined spaces could also have other hazards such as:

  • Low ceiling height causing personnel to crouch and move inside. Chances of banging head onto appendages and the ceiling can exist.

  • Low or nil visibility since the space is not lit well.

  • Slippery surfaces due to stored chemicals and even water.

  • defective or missing ladder rungs in the space

  • Falling objects; this could be from people working at higher levels within the space or material being removed / being cut.

  • High temperature within the space due to exposure of the external surface to hot sun or low ventilation in the surrounding compartments. Periodic rotation of staff working inside is essential to reduce fatigue and dehydration.

  • Noise is another hazard. Sounds may get amplified beyond allowable limits, within the space.

Personal Protection Gear

Though the list is not exhaustive, the following are considered essential:

  • Chemical suites in case of entering spaces containing hazardous chemicals

  • Industrial safety helmet, preferably with a miner’s torch on it.

  • Breathing apparatus (Self contained or with re-circulation depending on the space content and current state) when the Oxygen levels are low or hazardous gases are still present.

  • Ear defenders / plugs

  • Eye protection

  • Non skid safety shoes with rubber soles and steel toe caps

  • Work gloves

  • Fall arrester or full body harnesses; to be used while entering and leaving the space and if working at a height within the compartment.

  • Safety communication and rescue rope lines. If the person working within the space is visible to the support person outside, rope communication lines are not necessary and voice communication can be resorted to.

  • Lead lamps from a low voltage DC source

As part of the Hazard assessment, confirm whether the person entering the space can enter through the available opening, wearing all the protective gear and can be evacuated also in the same state. If not possible, alternative strategies will have to be devised.

Support and Emergency Team

No one should be allowed to enter a confined space without at least one person standby, manning the communication rope line, outside the space. The emergency rescue team should be in a quick access position to attend in case of emergencies.

Each person entering the space should have a buddy outside monitoring his progress.

The rescue process should be planned in advance and practiced regularly. An unplanned rescue act could endanger other lives also.

The people entering confined spaces and the support team are to be fully briefed about the hazards, work needed to be done, work process flow, who-is-to-do-what, sequence of entry / exit, tools and other material to be carried etc.

First aid kits with all essential material should be kept handy in the vicinity of work, with the support team.

The communication signals should be mutually agreed and understood by all. These should be practised too to identify the difference between a quick tug and a long pull. A Few examples are given below:

  • One quick tug every 5 minutes would mean everything fine

  • Two quick tugs could mean that he needs something from top

  • Three quick tugs could mean he wants to send something up

  • Long pulling on the rope or frantic tugging means he is in trouble and needs help

  • No tugs or pulls for more than 10 minutes would mean immediate assisted evacuation of the person from the space.

It is worthwhile developing a “Standard Operating Process” (SOP) for any work related to confined spaces, so that it becomes part of a standard drill by all concerned.

Part 3 of this series will have a check off list that can be consulted and confirmed before undertaking work within confined spaces.

Safety Matters, While Working in Confined Spaces Part 1

This article has been written out of personal and institutional experiences and should not be taken as a formal guideline for working in confined spaces. Please refer to relevant safety manuals before undertaking such work.

Definition of Confined Space – A space that has any one or multiple characteristics indicated below is deemed to be “Confined Space”:

  •  Limited number and / or size for entry and exit for the space. Examples – Water tanks / Fuel or oil storage silos / Manhole chambers in sewerage lines etc. Man hole sizes may be very small restricting fast movement. There may be just one manhole provided in a tank.
  • Unfavourable natural ventilation. Example – Water and oil tanks are normally kept hermetically sealed to avoid contamination from outside, hence there is no natural ventilation. Manholes in sewerage lines may have some ventilation due to its widely connected network but may not be able to sustain life. Toxic or inflammable gases may occupy the spaces.

  • Not designed for worker occupancy normally. ExampleThis could be material storage rooms in basement areas, with very low or no ventilation due to various reasons. May not have life-sustaining gases, but may have other non-life sustaining or toxic gas concentrations.

Some of the confined spaces found in workplaces may have a combination of all the above characteristics, complicating the working within the spaces and emergency rescue operations. Hazards identification needs to be thorough and foolproof in all the above cases.

Hazardous Atmospheres

The atmosphere within a confined space could become hazardous because of lack of natural air movement. This could lead to the atmosphere being:

  •  Oxygen deficient (Less than 19.5%). An existing atmosphere within a confined space may be Oxygen deficient. Further Oxygen depletion could occur due to human physical activity within, welding, cutting, chemical reaction (rust formation, fermentation etc). Oxygen could get displaced by heavier non life-sustaining gases such as Carbon dioxide or Freon or Hydrogen Sulphide. If the Oxygen level is less than 19.5%, entry is to be restricted and allowed wearing Self Contained Breathing Apparatus (SCBA) only.
  • Toxic. Toxic atmosphere could be found in confined spaces due to:

    • Gases coming out of the residue left in the tank even after the bulk of the material has been evacuated. This could be sticking to the side walls or settled to the bottom of a tank. Dangerous Hydrogen Sulphide gas can emanate out of decomposed material.

    • Even fresh water tanks could have hazardous gases such as Chlorine which is not life-sustaining.

    • Bi-products of work such as cutting / brazing / painting / cleaning /  can form a hazardous mixture of gases within confined spaces.

    • Gases from an adjacent compartment or work space could enter a confined space and remain trapped there.

    • Material handled could form concentrated toxic gas areas, even with partial ventilation. Sewerage inspection chambers could trap lethal gases from the sewer.

  • Flammable. When three essential components, namely, (a) presence of Oxygen, (b) a flammable mixture of vapour / gases / dust and (c) a source of ignition are present together in a space, fire and explosion are inevitable. Different gases / vapour / dust have different levels flammability. A small electric spark from a motor or even a breaker contact could form the source of ignition. An oxygen enriched atmosphere (with more than 21% Oxygen) can cause inflammable material to auto-ignite and burn violently.

To be continued in Part 2 of this series. Part 2 contains thoughts on “Testing the atmosphere within confined spaces”, “Isolating the confined spaces”, “Other likely hazards within confined spaces”, “Personal protection gear”, “Support team” and “Training” aspects.