Stresses in Piping systems

Hi all,

This is one of my favourite topics, since I had a large number of systems piping failures related to stress, mostly external.

One of the flange connections of the fire main systems on board a ship, couple of bolts used to break at the head frequently; more often if the ship had done some high-speed manoeuvres.  Initially, we used to change the bolt and live with it, but a nagging doubt came into our minds and we did a root cause analysis. What we finally found was that, the last pipe that fitted into the system was a little oversized and had been forced into its slot using a chain pulley, thus leading to a stressed piping section. Whenever high vibrations occurred, the stress used to increase, thus resulting in the flange securing bolts at one end shearing.

I came across a nice article on the topic. Please read and be enlightened on the topic.

Is-your-piping-system-prepared-for-stresses

KayCee

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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

Operations-driven reliability

Hi all,

In some of my earlier posts I have spoken about reliability, simple “Look, Listen, Feel” strategy in condition based maintenance strategy etc.

I came across an article in “Plant Services” web site covering a few of the areas and working towards “Operations – driven reliability.

I conducted a workshop on Reliability Centred Maintenance where I had covered the aspect of “Managing User / Client / Operator” expectations.

Please read this article following the link given below.

Operations-driven reliability.

Kaycee

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

Cleaning Glazed Areas – The challenges

Hi all,

Two small disclaimers are necessary in the beginning itself:

  • all the opinions voiced in this Post are my own and not that of any organisation that I worked with or am currently working with.
  • Some of the descriptions of buildings and problems faced therein are mentioned in this post, without actually naming them or giving out their locations. If the readers find some matching buildings in their own imagination or experience, it is their own imagination.

Glazed facades / domes / atrium roofs

Glass has been a great building material for quite some time. The technology improvement in making plate glasses have brought in a large variety of glass in various hues, colours, sizes and shapes available to the architects and building engineers. What this has brought about is large glass facades, walls, doors, etc at times measuring a few acres of surface area in a building.

The artistic domes atop buildings and atrium roofs add style and glamour to buildings.

Glass has become an integral part of every building in view of meeting the “Day light harvesting” requirements, grand facades, reducing stored heat or cold as the case may be and other architectural interests.

Maintenance challenges

When compared to painted or other types of external wall coverings, glass offers a longer time line between maintenance cleaning and other work on them. The smooth glass surface is less likely to retain debris, dust and moisture compared to rougher painted surfaces and porous natural stone coverings. The use of a combination of glass and aluminium cladding for facades has caught on like wild-fire.

Not withstanding the above facts, glazed exteriors also require periodic maintenance – this is an inescapable fact.

Architects, building engineers and building / facility owners also need to be aware of the glazed area maintenance requirement at the building design stage itself. If the maintenance related provisions are made at the design stage, the implementation of periodic maintenance becomes easier and fool-proof. I am going to cover the challenges in glazed area maintenance in a series of case studies.

Case 1.  Small factory building with glazed facade

In this building the glazed area was basically for show purpose. The architects had not provided any means to do glass cleaning. The height was not much, but more than what was reachable even with the longest telescopic glass cleaning equipment. There were no accessible perches in between, to provide access. There were no anchor points provided on the flat terrace, to allow people to access from the top. The dusty external environment made the facade dirty very frequently. As the Facilities Management agency for this building, we suggested procurement of a scissor / boom lift for the facade cleaning purpose. the same equipment could be used for other purposes such as high mast light fitting maintenance, accessing the steam / chilled water / DM water pipes running on raised structures etc. It was a worthwhile investment wisely made by them.

Safety Factors in Using a Scissor / Boom Lift

Only a trained and authorised person should be allowed to drive and operate the scissor / boom lift. The driver may not necessarily go up with the lift while the cleaning person is on task. The driver needs to be around to assist in changing the height of the boom, moving it to the sides etc. These operations / controls of the boom bucket should be with the driver alone.

The people undertaking the cleaning should wear all essential PPE such as safety helmet, nose mask and eye protection (in case of flying dirt and debris) and a full body safety harness that is anchored to the boom bucket anchoring points.

Scissor / Boom lifts should be parked in more or less level ground, before the people are lifted up. Positive additional support using hydraulic jacks should also be applied.

Case 2.  Very well-known education institution with a large academic centre with a deep atrium and tall central structure

The architects had chosen natural stone for covering the external walls. The stone colour would not show much of the dirt that settled on its rough surface. The central tower was totally air-conditioned, hence had sealed windows. There was no way to access the window panes from the outside since it was too tall to reach from the atrium. Atrium was accessible only through staircases, thus ruling out a boom lift or other types of vehicles entering there and being used for access. Yes, we could have lowered a vehicle in using a heavy-duty crane, but the vehicle would have been constrained to remain within that area and would have been underutilised.

There were no anchor points provided on the terrace. The terrace layout and structure were not amenable to lay a trolley for a davit and cradle arrangement to move around the periphery. The management was not very keen on making a big capital expenditure for the facade cleaning equipment also, since it was not budgeted for in the initial plan.

Yes, spider man technique using improvised anchor points could have been used.

I am not aware as to how they finally managed, since I left the facility for other new projects and at a later date my company stopped working in that facility too.

Case 3.  A Tech Giant with a large office space completely covered with glass all around

In this case every thing was provided for. A clean rectangular foot print for the highrise building allowed clean runways for the davit to run on the terrace and enough space to lower the cradle at all positions. Good quality, known brand of cradle mechanism was installed and operated as well.

Safety Factors in Using Cradle Mechanism

The people using the cradle mechanism are to be trained, tested and authorised for using the same. Periodic refresher training and testing are also required. “Train the trainer” route also could be taken on the long run to train a couple of internal trainers, thus reducing the recurring training cost.

All essential PPE should be issued and used by the people assigned to the cradle work.

Work permit should be issued after ascertaining the safety aspects and hazards analysis. The wind speed should be a maximum of moderate levels only – otherwise too much of swinging of the cradle could lead to accidents, banging onto the building facade, damage to the facade including glass etc.

Review of load test certificates, ropes and other load bearing members of the cradle arrangement should be done before attempting to operate. All periodic statutory tests and certification are to be current before starting operations.

The building owner and users should be briefed about the facade cleaning work plan.

Necessary barricades for risky areas, security personnel posted at tactical positions to guide other users and full supervision of the work are essential to ensure total safety.

Case 4. An automobile manufacturing plant with a network of long interconnected production bays.

The designer had provided for “Northlight” glazed areas in each bay. The roofs were slanting type, with sheer falls at the northlight area. All the glass panes were sealed to their frames to avoid ingress of water during rain. The glazed areas were not accessible from the ground due to height and other structures blocking the path for boom lifts. The only access was from the roof. Climbing on the roof itself was a hazardous exercise, due to the complex structures and the slope.

Representative Northlight roof structureJust to help in visualising the problem, a representative drawing of the bare structure is given here.

The cleaning from inside was comparatively easier since the cleaning crew could climb on the internal structure and reach the glazed area.

Much thought was given and ideas were discussed before reaching the ultimate decision on how to safely work on this job. A steel rope was anchored to both ends of each bay and tightened as far as possible. These ropes were further anchored to some points on the lower side of the sloping roof, so as to keep the rope as taut as possible. The work platform was hung on to the rope with a pulley arrangement to lower and hoist. People working from the platform were anchored to the rope using extension bits and the full body harnesses.

Getting the “Work permit” each day was a mammoth task since the Company management wanted a zero accident record. We managed the same without any mishaps barring minor abrasions to a couple of people.

Tail Piece

Imagine the team that does facade cleaning on the World’s tallest tower “Burj Dubai” and other such buildings!

The idea behind this blog entry is to get the regular readers thinking on the right lines from the building design stage till the regular maintenance.

Comments and suggestions are welcome. Thanks in advance!

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