Sunday, July 13, 2014

Preparing Engine room for dry dock.

25 Important Points to Consider While Securing the Engine Room for Dry Docking

By 3 Comments
Once the vessel enters the dry dock for hull inspection, it is important that the ship’s engineer secure the ship’s propulsion plant and the engine room in the correct sequence to prevent any kind of damage or problem while restarting the plant once the dry docking of the vessel is finished.
Following points must be considered once the ship enters the dry dock and before emptying the water from the dock to rest the ship on the keel blocks:
1. Ensure all the tanks in the engine room are at required level as demanded by the chief officer to achieve required trim for docking.
Related reading :
Maintenance of small tanks in the ship’s engine room , List of some important tanks on ship, List of fuel, diesel, and lube oil tanks on ships.
2. Shut down all the auxiliary engines except one for providing the required power
Related Reading:
- Procedure for starting and stopping generators, Important signs indicating auxiliary engine needs overhauling, A step-by-step guide to overhauling generators on ships.
3. Isolate sequential start system for generators
Related Reading:
How to synchronize generators on ships?, Important points to consider while carrying out alternator maintenance of ship’s generator, Important points for major overhauling of ship’s generator
4. Shut steam to jacket cooling water system
drydock
Related Reading:
General Overview of Central Cooling System of Ships
5. Keep the jacket cooling water pump running  until the main engine is gradually cooled down
6. Transfer the main engine lube oil in the sump to lube oil settling tank by using purifier
mairne engine
Related Reading:
Ways to optimize lube oil usage on ships
7. Ensure all auxiliary engines are shut down except one diesel engine supplying enough power
8. Before shutting down all the auxiliary engines, ensure they are changed over to diesel oil
Related Reading:
Fuel oil change over procedure
9. The main engine should be changed over to diesel oil prior one hour of docking. If not, changeover to diesel oil with fuel oil service tank return valve open until line has been flushed with diesel oil
10. Shut down lube oil and fuel oil purifiers
11. Shut down deck machinery system and isolate it from main switchboard
Related Reading:
Safety Devices for Main Switch Board 
12. Shut down and isolate the auxiliary boiler. Allow it to cool naturally and once the pressure is below 1 bar, open the vent
Related Reading:
Shutdown procedure of boiler
13. Once the boiler is shut down, stop and isolate the feed water system and distillate tank
14. Circulate diesel oil in the boiler fuel pipeline system before shutting down the fuel oil pumps
15. Shut down the stern tube lube oil system and if required, drain the lube oil system back to stern tube storage tank
16. Shut down the accommodation air conditioning system and refrigeration plant until the shore supply is connected to the ship
Related Reading:
8 Common Problems Found in Ship’s Refrigeration System
17. Shut the steam to the alorifier and switch on the electrical heating system
18. Ask shore in-charge for water connection required for running air conditioning and refrigeration system
19. Isolate ship’s fire pump and connect the shore fire connection to ship’s fire line
Related Reading:
What is international shore connection?
20. Check the frequency, voltage and phase sequence of the shore power
21. Isolate emergency generator before connecting shore power
Related Reading:
Ways of Starting and Testing Emergency Generator 
22. Shut down the running generator leading to blackout for connecting shore power
23. Connect the shore power to emergency switchboard
Related Reading:
What is cold ironing?
24. Restart the jacket water pump for the generator until it is gradually cooled down to avoid thermal stresses. Once cooled, shut the pump
25. Secure the engine room fire fighting system including foam and CO2 fixed fire fighting system
Related Reading:
Mistakes not to make while handling CO2 Fire Fighting System
Inform the dry dock in- charge that engine room is ready for docking and dock water can be emptied.
Is there any other important points that should be added to the list? Let us know in the comments below.
For complete procedure of various dry dock operations for Engine Room Department, check out our ebook:
A Guide to Master Dry Dock Operations (For engine room department) is a downloadable ebook designed to help you understand the whole dry docking procedure is a step-by-step manner, right from the planning to sea trials.
Posted by at No comments:

How to know Generator need to overhaul

8 Signs That Indicate Your Ship’s Auxiliary Engine Needs Overhauling

By Leave a Comment
Ship’s auxiliary engines are the most important supporting pillars that keep the ship going. As a marine engineer working on ships, understanding the ship’s auxiliary engines is of prime importance in order to avoid sudden breakdowns or blackout situation.
However, ship’s auxiliary engines are not easy to tame. They need constant monitoring and maintenance for running at all the times and for preventing them from bringing the ship to a stand still.
Though routine maintenance and checks of auxiliary engines is a must, there are times when they  requires serious overhauling. As marine engineers, it is important to know the time and signs which tells that the auxiliary engine needs overhauling.
Mention below are eight signs to check in your auxiliary engine.
1. Generator Not Taking Rated Load
If the generator is not taking the rated load then there are chances that it is having some serious trouble. Signs like overall temperature of the engine going off-limit, important parameters showing abnormal figures and unusual fluctuations etc. indicates that the generator needs some serious checking.
generator overhauling
2. Power Imbalance
A ship’s engineer must keep a close eye on all the parameters, especially while taking performance readings of the auxiliary engine. If there is high peak pressure variation in any of the generator units as compared to the average pressure, it indicates that the combustion chamber needs immediate overhauling.
3. Degradation of Lube Oil
Examining the quality of the lube oil is yet another way to find out about the condition of the ship’s auxiliary engine. If it is found that the lube oil is degrading and needs to be removed before its running hours limit due to sludge formation, it may indicate blow past of the units. Such condition would require finding out the faulty unit followed by major overhauling.
Degradation of lube oil would also lead to choking of filters, major reduction of oil pressure, and sudden increase in differential pressure. It is important to keep a track of these signs as well.
4. White Metal Particles Found in Filters
If any type of metal particles (small or large) are found in the filters, it indicates that major wear-down of bearings is taking place. This would require immediate overhauling of the faulty unit.
5. Unusual Knocking Sound
Sound of the auxiliary engine is also one of the best ways to identify a problem. As a marine engineer working on ships, you would be quite familiar with the usual working sound of the auxiliary engine. If the “working sound” is replaced by any unusual knocking sound, it indicates that there is some problem with your machinery system.
Observe the knocking sound closely, if the sound is increasing at a faster rate, it is better to rectify the faulty engine as soon as possible.

6. Generator Over-Speeding
Over-speeding of generator is a situation wherein uncontrolled acceleration of the engine takes place, leading to mechanical failure and serious accidents. Mostly, it occurs during the time of starting, but can also occur when it is running on load due to fuel pump getting stuck or problem in the fuel system. Check if your engine is over-speeding and take measures accordingly.
7. Abnormal Crankshaft Deflection Readings
A marine engineer has to take timely measurement of crankshaft i.e. crankshaft deflection with the help of dial gauge. If the readings are above the normal limit, it indicates problem in the main bearings or alignment of crankshaft, requiring immediate action.
8. Running Hours 
Last but not the least, keeping a track of the running hours is extremely important to know when the engine would require next overhauling. Read the past records and carry out timely overhauling procedures.
These are some of the important points to figure out if your auxiliary engine requires complete overhauling. Do you any other ways to find out problem with auxiliary engines? Let us know in the comments below.
D’carb or major overhauling of a ship’s generator is a very tedious task for marine engineers on board. Following a step-by-step procedure backed by systematic planning is the base of a successful generator overhauling procedure.
Posted by at No comments:

Knowledge for onboard inspection

The best way to deal with fires on board ships is to prevent them rather than letting them occur. Breaking out of fire in a place where no fire exist is called “ignition”, whereas “flash” is a term used for fire eruption in a new place as a result of flames from an existing fire in a nearby place (the ignition source).

Fires on board ships can be prevented by finding and rectifying leakages of fuel oil, lubricating oil, and exhaust gases.

In a ship’s generator room, the biggest danger of fire is from a leaky high pressure fuel pipe. Oil leaking from such pipe can fall on high temperature exhaust manifold or on indicator cocks, which are sensitive points for catching fire.
In modern marine engines, there is push-type cover concealing the indicator cocks; however in old engines there is no such provision available which makes it quite difficult to provide lagging to indicator cocks.
These days fuel high pressure pipes are sheathed and the leakage finds its way to a small tank at the bottom of the engine known as fuel leak off tank. It is imperative to keep this system in good order by regularly testing the tank alarm – fuel leak off tank high level alarm.
Leakages are mainly caused because of pipes breaking due to vibrations, clamps rubbing against pipes to create holes, pipe connections behind the pressure gauges getting damaged due to ageing (we generally do not look here), leakages from fittings at boiler furnace front and incinerator front etc. These leakages are some of the most common “hot spots” for fire. Moreover, careful and periodical checks are also required on boiler smoke side and incinerator uptake.

Fires can be largely prevented by providing effective laggings to hot surfaces such as generator turbocharger bellows, main engine exhaust uptakes after the turbocharger, various steam pipes and pipes carrying hot oil. Laggings can be done by ship staff but these days specialist contractors are available to carry out this work more aesthetically. Also, whenever lagging is removed, a habit should be cultivated to put it back after the work is finished.
Apart from this, it is also important to check/test fire detectors on regular basis. Some of the main types of detectors used on ships are:
Flame detectors 
Light produced by a flame has a characteristic flicker frequency of about 25Hz. The spectrum in the infra red or ultra violet range can be monitored to give an alarm. Oil fires generally do not give off much smoke and this type of sensor is preferred, especially near fuel handling equipment or boilers to give an early warning.
Heat detectors
Heat detectors are of various types such as rate of rise type, which has bi-metallic type detecting elements – a thick strip and a thin strip. The thin strip is more sensitive to temperature rise than the thicker one.  If there is a sudden rise in temperature, the thin one bends faster than the thicker one, bringing both of them in contact.

During normal temperature rise both strips will deflect about the same amount and thus show no reaction. Normally if rate of rise is less than 10 deg C in half an hour, the detector will not give any alarm. If the rate should rise to 75 degree Celsius, or more, the two strips come in contact, thus triggering the alarm.
Smoke detectors
There are two main types of smoke detectors used
1) Light obscuration type
2) Ionization type Liquid or gas fires may not give off smoke initially but will catch fire spontaneously. Thus smoke detectors are not effective for such fires. These detectors are mostly used in accommodation areas.
Important points to consider for fire prevention on board ships
  • In engine room, waste bins used for storing oily rags must have lids (covers). Oily rags should not stay lying around or stuck at unnecessary places. Receptacles with covers should be provided at each floor and on both sides.
  • High pressure fuel oil pipes should not be tightened to control a leakage while the engine is running. Also, oil shouldn’t be taken in to turbochargers during operation.
  • Short sounding pipes should be kept shut with plugs. Never should they be left in open position for the sake of convenience. Cases have been reported wherein oil has spilled out from these short sounding pipes leading to accidents.
  • Loose pet cocks /small cocks on common rail pipes should be checked for.
  • Exhaust leakages and steam leakages should be promptly attended.
  • Ship’s crew should be careful about galley fires, especially by keeping electrical equipment in good order. Senior officers should keep an eye in the galley when provision is being received because this is the time when galley remains unattended for a long time.
  • One of the patent methods of fire prevention is effective and regular fire patrol. There is no method that can beat physical monitoring.
  • Fire caused by cigarettes is still one of the most common causes of fire. All care should be taken to dispose cigarettes (using self closing ashtrays) and never should one smoke in bed.
           
  • Fires have also caused during loading and unloading of cargo such as coal. For this reason, ship personnel must always discuss the characteristics of the cargo and preventive methods to be taken during safety meetings and weekly drills.
These are some of the main points one needs to consider for a safe environment on ship. This list might not feature all the methods to prevent fire; however it does provide a brief overview of how things are to be handled on board ships.
Do you have more useful tips to prevent fire on board ships?
Image Credits: exportlogisticsguide, maritimesafety, expedo

Posted by at No comments:

Wednesday, July 2, 2014

Making Sure Steam Piping Is Safe(10 Simple Rules and Things to Look For)#.U692uodzWi0.facebook

Making Sure Steam Piping Is Safe(10 Simple Rules and Things to Look For)#.U692uodzWi0.facebook

Making Sure Steam Piping Is Safe(10 Simple Rules and Things to Look For)

Tue, 06/28/2005 - 7:42am
This document seeks to provide methods for screening high pressure (below 300 psig) piping systems, that may normally be encountered in industrial steam plants, to identify safety issues related to the design and/or installation of pipe, valves, flanges, and components used in these systems. The following is not an all inclusive guide to safe practices, but instead attempts to give some insight for understanding and conducting a simple screening of a steam piping system. This review of what is installed is important for every steam plant operator to help make sure that an unexpected accident is not waiting the next time someone opens a valve or puts a steam line into service.

1. Steam Piping Ratings of Boiler Systems
In most states and jurisdictions, steam piping is classified as high pressure piping when it exceeds 15 PSIG. The main construction code used to define high pressure piping issues and requirements for construction and installation is published by the American Society of Mechanical Engineers (ASME) Section I (Power Boiler) and ASME code B31.1 (Pressure Piping) codes. You can obtain copies of these code sections at www.asme.org or by calling 1-800-THE-ASME.

2. MAWP - What is it?
The piping, valves, and components of any high pressure piping system have to be rated for the MAWP, or the Maximum Allowable Working Pressure, of the boiler. ASME requires a nameplate be affixed to the boiler with this information on it. The piping attached to the steam discharge flange must also be built to withstand the MAWP that the boiler can generate. In multiple boiler installations, the design rules typically apply to all piping through the second stop valve from the discharge flange of the boiler and are governed by ASME Code Section I and B31.1. After the discharge of the second valve, the piping must be rated as required by the applicable jurisdiction. This may be the MAWP of the boiler or at least the setpoint of the highest safety relief valve protecting the system. There are also specific rules for stamping or identifying the piping which falls within the code boundary jurisdiction of the boiler. Typically the S/N (serial number), Certified By and Pressure will be stamped or a nameplate banded to the pipe indicating this information.

3. Some Piping Basics
It is very important that you understand what you are looking at and the consequences of being wrong when it comes to evaluating piping systems. Let’s start with the pipe itself. Most pipe you will ever encounter starts its life at a steel mill in sheet form. In many cases, the mill rolls the sheet into tubes and welds it. There are different piping designations, an example is ASTM A 53B, ASME SA 53 B. ASTM means American Society of Testing Materials, (www.astm.org), SA 53 B, is the designation for plain black steel pipe mostly used in the industry. Piping also comes in different schedules (or wall thicknesses). The schedule or thickness would be schedule 40 or 80. The wall thickness for typical 6 inches schedule 40 increases from 0.280 inches to 0.432 inches for schedule 80. Schedule 40 is what’s commonly called for in B31.1 for pressure piping in service conditions that apply to this article. B31.1 and ASME code, Section I, have calculations that the designers would use to determine the safe working pressure of the piping based on its type, thickness and minimum diameter. Schedule 80 is called out as good practice for most condensate systems since they are a severe duty as compared to steam. Condensate is likely to contain carbonic and or other mild acids. This tends to erode condensate piping over time. Making this kind of piping thicker from the start builds in a factor of safety.

4. Flanges and Their Ratings
You also need to be aware of flange pressure ratings. The ratings and certification information are usually stamped on the circumference of the flange. A 150 LB flange indicates a pressure temperature rating. This is not the MAWP of the flange, but a designation which allows a certain pressure use based upon the installation and temperature to be encountered. Pressure /Temperature ratings can be found in ASTM A 105 B 16.5 specification tables (www.astm.org).

5. Flange Materials
Flange materials can also be tricky. You always want to make sure you are using carbon steel flanges with the proper rating, A 105 B 16.5 is a typical carbon steel flange used in pressure piping applications. Cast Iron flanges are too brittle and could break in this kind of application.

6. Fastener Issues, When a Bolt is Not Just a Bolt
Fasteners could be another problem area. Fasteners should be rated to at least a grade 8. This means they have a tensile strength that could withstand the force that must be applied for the proper assembly of the components. There is also a standard marking system for fasteners. When you look at a bolt head you should be able to see markings that identify its grade or rating. Be aware that cheap fasteners can mean forgeries that can cost someone their life. You can find out more about fasteners and ratings by going to the National Fastener Distributor Association’s website at www.nfda-fastener.org. Also, be aware of threaded rods and studs. Studs are not simply some supply house off the shelf threaded rod cut to size. Studs should be marked with a stamping in the end that indicates they are a special grade and type of material that is of sufficient tensile strength. They might have a marking like “AB or HV” stamped into the end.

7. Joints and Joining Methods
Pipe gets assembled to other pipe, fittings, and flanges by either welding or threading. There are specific code requirements that describe when it is permissible to thread or when welding must be used. Within the welding world, you also need to be aware of several other possibilities. Flanges and fittings come as either slip on or weld neck. Slip on fittings are just that, slipped onto the end of the pipe. The flange is then welded up around the contact points on the inside and outside of the pipe and the flange. Slip on flanges are not considered as strong a joint as weld neck or butt welded connections. In the case of a butt welded or weld neck flange the two pieces, flange and pipe, are prepped and then welded together with full penetration through the weld construction (a welder carefully lays a bead and builds up layers around the entire surface of the gap between the two pieces). Socket welding is a term used to describe when a slip on fitting, usually used for small diameters, is inserted into the fitting until it bottoms out. Then the pipe is pulled back from the bottom and welded to the fitting. Failure to pull the pipe back can cause welds to fail from stresses.

8. Valve and fittings ratings
Valves and fittings should have their pressure rating cast into them or marked as required by the applicable material specification. Many pipe fittings are marked with a manufacturer’s logo or insignia, size, and schedule rating (example 6 inches SA 234 Gr WPB or 1 inches 3000M A105 B 16.5 with the logo). The pressure rating must be at least equal to the design MAWP. Again ASME/ASTM SA/A 234 or SA/A 105 B 16.5 give the specific requirements for these fittings. Valves will also be marked with their pressure rating along with the type of service permitted to be used. The ASME codes specify which types of valves and fittings are permitted to be used and their proper service applications in pressure piping applications.

9. Welding Considerations
Welding on pipe, fittings, flanges, and pressure vessels must only be done by someone with the proper credentials. Welding on pressure piping must be performed following qualified welding procedure specifications. It is the responsibility of the installer to have welding procedure specifications that are certified to meet the applicable ASME code construction;(refer to ASME code Section I and B 31.1 and ASME Code Section IX for welding procedure specifications). The National Board Inspection code which is required for repairs of pressure equipment also includes AWS (American Welding Society, www.aws.org) standard welding procedures. Every detail of AWS standard welding procedures must be followed when welding or the weld can be deemed to not be a qualified weld and in jeopardy of having to be removed.

10. Qualified People
Welders must also be qualified to the requirements of ASME code Section IX. Once qualified and certified, the welder can only weld within the variables listed on their welder’s performance qualification record. The welder must also weld within the process at least once every 6 months or the qualification expires. Records must be kept to prove that the welder had welded at least once every 6 months. Welders will mark their welds with stamping to identify which person welded which joint. This stamping could be there on your system but possibly obscured with insulation.

Along with the ASME required stamping, the National Boards registration numbers might also be found. The National Board of Boiler and Pressure Vessel Inspectors is located in Columbus, OH. They maintain a database of all registered pressure items. You can call them with the National Board number, original manufacturer and year built as indicated on a nameplate, and they can tell you lots about what you have and the original design. They can be reached at www.nationalboard.org. This is very important when inspecting, repairing or replacing items. The proper repair or replacement should ensure the same safety integrity as when the boiler, pressure piping or pressure equipment was originally constructed (If not better).

There it is 10 simple rules that might keep you or someone else alive. Trust me, you do not want to be around a piece of piping or a flange that lets go. We are talking the immediate removal of flesh, displacement of oxygen, and burns over so much of your body that it will be over in a painful matter of hours. This stuff is nothing to play with so make sure the job is being done right, use professionals, and know what you are getting. Also, take a little time to use the information above and know more about what you already have.

By John R. Ruskar and Mark Rudek
Posted by at No comments:
Subscribe to: Posts (Atom)