waratah boiler fire tube removal and replacement …

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C:\Users\tdrin\Desktop\BOILER\WARATAH BOILER FIRE TUBE REMOVAL AND REPLACEMENT REV 1.docx

WARATAH BOILER FIRE TUBE REMOVAL AND REPLACEMENT REPORT

June-July 2020

Report by Tim Drinkwater Date: 26 July 2020

Above Steve Stylianou Oxyacetylene cutting one of the plain tubes out of Waratah’s starboard side tube bank.

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Waratah

Boiler Fire Tube Replacement On the 29 May 2020 we blew down the Waratah Boiler to prepare for the removal and replacement of all the boiler’s fire tubes. The plain tubes were replaced 30 years ago but due to the thickness of the stay tubes, 8 mm WT, a decision not to remove, was agreed. During March 2020 our Engineering Team were consulted and a Board decision to remove and replace all Fire Tubes was agreed. This will give the Boiler more than another thirty (30) years of operational life if we operate the boiler within the designed parameters and if we continue using the correct chemical treatment for the boiler water as required. After the boiler was blown down the three boiler manhole doors were removed. This is very awkward and heavy task and unfortunately required two people to lift the manhole doors out of the boiler and boiler dome. Caution had to be taken due to Covid-19 social distancing. Before work started on the removal of the boiler tubes the combustion chamber and smoke box had to be cleaned of dust and ash. Once the furnaces were thoroughly clean the team were able to assess the condition of the boiler tubes and develop a process to cut the tubes out of the tube plates. Other work/tasks done before the tubes were removed were:

1. Prepared a Covid-19 Safety Plan 2. Prepared Safe Work Method Statement for the work to be done and implement all of the control

measure required to complete the tasks safely. 3. Confined Space Permit completed daily. 4. Hot Work Permit completed as required. 5. Removed the Furnace doors and Furnace Door Frame work. 6. Remove the Fire Bars and Fire Bar support frames. 7. Remove the Smoke Box Doors 8. Remove the combustion chamber/furnace fire brickwork to give better access to the combustion

chamber; safer access to and exit/extraction from the aft boiler tube plate. 9. Set up scaffolding in front of the boiler for better access to the smoke box tube plate; safer work

platform. 10. Set up Exhaust fans for appropriate ventilation required while working in the combustion chamber,

boiler interior and stokehold. The Process to Remove the Tubes.

1. Cut the Stay tube nuts off both ends of the stay tube. Smoke box end and combustion chamber end. 2. Cut the stay tubes approximately 75 mm inside both tube plates leaving a tube stub only remaining

in the tube plate. 3. Once the Stay tubes were lowered down into the bottom of the boiler they were extracted through

the bottom boiler manhole. 4. The remaining stay tube stubs are then gouged (oxyacetylene cutting) very carefully to prevent any

damage to the stay tube plate hole. This process was repeated three times around the circumference of the stub and then by carefully using a coal chisel to collapse remove. This process required a highly skilled boilermaker to complete the task without damaging the tube plate holes.

5. The plain tube removal is very similar to the Stay Tube. The section of tube that extends outside the tube plate is chiselled/collapsed towards the centre of the tube (See attached image). This allows the outside of the tube to break away from the tube plate which allows the oxyacetylene cutting to start gouging directly on the tube wall without damaging the tube plate hole. Works very effectively. After the tubes are removed the process off repairing the tube plate holes is required. It should be noted some of the tube plate holes had signs of previous repairs, 30 years ago.

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The threaded stay tube plate holes were ground out to a larger diameter especially the combustion chamber end of the boiler. Once the thread is removed a tube expander is used to roll the tube holes diameter evenly making sure that the diameter is equal through 360° of the circumference. This part of the tube installation preparation is very important so that a good seal is achieved when the new tubes are fitted and expanded firmly against the tube plate holes.

Once all of the repairs were completed the boiler tube plate faces were cleaned and prepared for the Magnetic Particle Test. A full report is attached below. The main purpose of this test (MPT) is to check that the ligaments between the boiler tube plate holes do not have any cracks or damage. These cracks may occur from the continued use of the boiler or the over expansion of the tube plates which may cause excessive load on the steel plate area between the tube plate holes; the ligaments. The final result was very good with only one small crack identified, as noted in the report, at the port side combustion end of the boiler. This crack, after closer inspection and repair, seemed to be the result of a peening chisel accidental striking the tube plate years ago when the last tubes were fitted to the boiler. The crack was very short in length, 5 mm, and was only 500 microns deep (0.5 mm) deep. The crack was machined out with a hand electric grinder, welded, machined back smoothly and tested again with a positive result.

In magnetic particle inspection, circular magnetization is used to detect lengthwise cracks. Passed through the part or through an electrical conductor within the part. The circular magnetic field cutting across the crack attracts and holds iron powder, to indicate the invisible defects. Very clever technology.

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Waratah’s Magnetic Particle Test Report from LAMATS

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Removing the Steam Drum and Dome Manhole Doors.

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Steve Stylianou is extremely experienced with regard to removing and replacing boiler tubes. In his past life, as an owner and operator of Maxitherm, he has re-tubed hundreds of boilers and expanded thousands of fire tubes and water tubes. This kind of experience is very rare and we are fortunate and grateful to have Steve on our team. He is also a valued member of the volunteer team at Rozelle Shipyard. Steve and Alex Majoribanks have recently removed the boiler tubes of the port side boiler of the John Oxley. The process was exactly the same except that the Waratah boiler is an operational boiler and of course slightly smaller.

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Tube Plate Hole Dimensions Analysis (Ian Roy)

Should note the combustion chamber tube plate holes have been machined just proud of the outside diameter of the fire tubes but the smoke box tube plate holes are 4 mm larger in diameter. As you can see from the data above the combustion chamber tube plate hole diameter range from 83.6 max to 77.6 min. The smoke box tube plate holes range from 87.5 max to 83.4 min. The new fire tubes, both stay tubes and plain tubes are 82.5 mm diameter. The Plain tubes are 4.064 mm

wall thickness (WT) and the stay tubes are 8 mm WT. More details of the Fire Tubes can be seen on page 7

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Tube Expanders

The images above show the two tube expanders that we purchased from Field Machine Tools Pty Ltd, FMT. The expander, top image, is for rolling the tube holes and preparing them for the boiler tubes. The tube expander, bottom image, is for expanding the plain tubes. This expander is also designed to flare the tubes at the same time. The tube expander we are using for the stay tubes was already in our Rozelle store. (Note it was restored by our boiler making team. A saving of approximately $1500.00.)

Old plain tube section showing how

the tube expander fits into the tube

Plain Tube Expander with flaring rollers

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The Process of Ordering the Boiler Fire Tubes There are twenty six (26) stay tubes and sixty (60) plain tubes. The stay tubes are OD 82.5 mm, WT 8 mm,

(5/16”) and the plain tubes are 0D 82.5 mm, WT 4.064 mm (8#). We ordered these from a Queensland

Company, Boiler Tube & Pipe, 184 Old Bay Rd, Deception Bay. QLD. 4508 PH: (61) 7 3204 1574 FAX: (61) 7

3220 6199 MOBILE: 0418 193 858 EMAIL: [email protected]

The tubes were ordered on Thursday 21 May 2020, a total cost of $14,783.78 delivered to our store, Gate 4

James Road Rozelle.

SPEC: Seamless Tubes to EN10216-2 P235 GH (German Manufacture) – Material Certificates to be supplied.

QTY / SIZE: 132 Metres (60 Pcs) 82.5 O/D x 4.00mm WT x 2.200 Metre cut lengths.

PRICE: AUD $ 54.50 per Metre delivered to your Rozelle. NSW. Store plus GST

QTY / SIZE: 57.20 Metres (26 Pcs) 82.5 O/D x 8.00mm WT x 2.200 Metre cut lengths.

PRICE: AUD $ 97.50 per Metre delivered to your Rozelle. NSW. Store plus GST

AVAILABILITY: Ex-stock Germany subject prior sale; allow around 1-2 weeks for cutting & packing plus 10 –

12 weeks for shipping and local freight for delivery to your Rozelle Store. NOTE: Delivery may take longer

due to the current Corona Virus situation throughout the world. Estimated ETA when this report was

written is 15 August 2020.

On the 8 June the Tubes were cut to length 2200 mm and packed and made ready for shipping from

Germany. See images below.

The tubes above have been cut to length (2134 mm plus 66mm), to compensate for potential

damage during transit, bundled and ready for shipping. All tubes are stamped indicating

dimensions, material specification, both stay tubes and plain tubes. While writing this report

the Ship, ALP Mexico City was in the Indian Ocean. Lat. 27.49182 S Log. 81.7583 E – 26 July

02:42 UTC

about:blank

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Stay Tube Certificate

Plain Tube Certificate

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Microsoft Project Management Plan

Waratah’s Boiler Fire Tube Replacement SWMS (Cover Page)

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Above is the covered page extract of the Safe Work Method Statement for the Waratah Boiler Tube Replacement including the Covid-19 Safety control measures. Because of the work being done on the boiler is high risk work a comprehensive Safe Work Method Statement was developed which included the requirement of a Hot Work Permit, Confined Space Permit & a Covid-19 Safety Plan. See attached document with this report.

Also above, previous page, the Microsoft Project Plan indicates the new boiler tubes will be finally fitted and tested early October 2020. This of course depends on the arrival of the Boiler Fire Tubes arriving from Germany in the middle of August 2020. The total estimated cost including labour and materials is $68,076.00

When this report was written the Boilermaker Team had rolled 50% of the tube plate holes and were planning to complete the remaining tube plate holes the following week.

The Screenshots, above, show the position of the Cargo Ship, APL Mexico City at 1300 hours AUS ETA, 26

July 2020. This is the vessel that is carrying our Boiler Tubes for the Waratah from Germany.

As you can see the ETA for Sydney is 4 August 2020. There will be some delay, approximate 7 days before

the tubes are given clearance from the Port of Botany to be trucked to our Rozelle Shipyard.

Reported By

Tim Drinkwater

SHF Operations Manager

26 July 2020

waratah boiler fire tube removal and replacement …

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