Boiler Survey on ship is an important task to be carried as per the classification society requirements. A lot of planning and work force utilization is needed. Let’s peek in to as how to plan this and tips to do this efficiently.
Requirement of Boiler Survey On Ship
The reason is simple. You need survey to make sure that machinery works as per the nature it is intended to. And regular survey makes the checks to be done in a better way.
For high pressure boilers, the duration is every 2 years and for low pressure boilers that duration is every 2 years till 8 years and they every year after that.
Preparation for boiler Survey on Ship
Preparation of boiler ranges from the paper work to actually opening of the boiler. Here I have divided it in parts:
As chief engineer you are supposed to mail the survey regarding the survey and what all things he or she would like to check.
As a 2nd engineer you need to plan the opening of boiler in advance. This will include managing of manpower required for same. Since surveys are done in port (which itself is very busy) manpower utilization is of utmost importance.
Later you need to prepare arrangement for hydraulic testing of boiler, which includes making a hand pump for hydraulic testing.
Gaskets for manhole doors (original from maker) should be there. Tools and locks required for the boiler needs to be prepared in advance.
If your ship have a single boiler, it will be wiser to change over all the machinery to Diesel oil or MGO before reaching port as there will be no heating available. Top up the DO service tank.
Starting With Boiler Survey on ship
1) Make work permit and all the team members are to be advised about the events that will take place and also what they are supposed to do.
2) Stop all purifiers and bunker tank heating. And any other machinery that needs steam. Put electric heater in use for the hot water calorifier.
3) Stop the firing of the boiler and let the steam pressure drop gradually.
4) When the pressure reaches 1 bar. Stop the water supply pump and close the feed valves. Also close the main steam valve.
5) Keep an eye on the boiler water level.
6) Now switch of the breaker for power supply to the control systems of the boiler.
7) Swing out the burner and let the furnace be ventilated.
8) In the mean time when pressure in the boiler reaches 0.5 bar, open the vent on the top of the boiler. Make sure that it is not fully opened in the first place as lot of steam comes out. So crack open slowly. Reason why we are opening vent is that to avoid vacuum developing in the boiler and damaging it.
9) Now when all the steam has come out and no pressure in the boiler, it is time to drain it fully. Bottom blow down valve can be used. You can collect this water in a separate tank if arrangement is given. This is to avoid wastage of chemical.
10) Now slowly open the top manhole doors. First slack them and tap gently.
11) Now open the bottom manhole doors and make sure that you are away at a distance. This is to avoid hot water coming to you.
12) Let the air ventilate through and it will cool down the boiler further. Make proper lighting arrangement inside. Keep safety kits like breathing apparatus ready.
Checks to be done during boiler survey on ship
Following items or mounting of boiler to be checked:
1) Safety Valve
Both the safety valves to be completely dismantled and each part to be checked thoroughly. Also the seat faces needs to be checked. Check spring length and compression.
2) All the mounting are to be removed and checked for proper condition. This may include all the valves like main steam valves, feed valve etc.
Read here: All the mountings on the boiler
3) Also the gauge close to be open and the gaskets are to be checked and replaced if found unsatisfactory.
4) The furnace needs to be cleaned with brush and water. All sediments to be collected and take out of the boiler.
5) The water side to be scraped with brush and hose down with distilled water. If the dirt inside is too much, then it needs to be filled the maker given chemical and should be cleaned. All cleaning inside the boiler either, smoke side or water side, should be done as per the instructions given by the maker.
6) Check the health of the tubes and also check for any kind of corrosion
- Check for corrosion
- Check tubes for any pitting
- Check for any local heating or deformation
- Check condition of refractory and repair as necessary
- Check for any kind of cracks etc.
7) If hydraulic testing of the boiler is required, then first of all the cleaning to be carried out and all mounting should be put back. All hand holes and manholes to be put back with new gaskets.
8) Make sure that the all the openings are closed.
9) Start filling the boiler with water till water comes out of the vent.
10) Connect the hydraulic hand pump (uses water) and raise the desired pressure as per the maker instructions.
After these tests and checks, boiler to be prepared for firing up. All the systems like water and fuel to be put back to normal as it was.
Note: The safety valve still needs to be set and tested again. This will be done after the boiler have been successfully fired up. The firing technique and warming up procedure to be done as per the maker instructions. This is to avoid thermal shocks developing inside the boiler. The setting of the safety valve of the marine boiler will be done in the later articles.