Bulging of boiler’s furnace shell at a Hotel, Bandar Baru Bangi

The purpose of this safety alert is to raise awareness among public, competent personnel, and workers who are directly or indirectly involved with the use, operation and maintenance of steam boiler - regarding the accident involving a steam boiler which is used by a hotel around Bandar Baru Bangi. The root causes of this accident can be possibly due to the combination of one or more of these factors: low water, mis-alignment of furnace nozzle, the formation of scales on the furnace wall on the water side and operation which does not comply to DOSH’s safety requirements.

It is important for employer or safety and health officer to make good observation regarding the responsibilities of the competent person who is in charge for operating the steam boiler to avoid any bad occurrences.

The boilerman should ensure the safe use and operation of the steam boiler at all times during his charge in order to prevent the accident like this from occurring.

 

 Figure 1: The bulging defect on the boiler furnace [looking from the fire side]

Preventive measures

1. The accident like this could happen if the feed-water is not properly treated and this may cause formation of scales on the water side. So it is important, for person in charge of the steam boiler to follow any instructions issued by the employer or any firm that undertakes the feed-water treatment.
2. Unfortunate event like this, is normally due to the localised heating phenomenom, where the heat transfer from the furnace shell to the water side is concentrated only in certain area of the furnace shell. The possible reasons for this phenomenom:
   1. there is no medium that can absorb the heat transfer from furnace shell (especially during the low water level condition;
   2. the formation of layer of scales on the waterside which blocks direct heat transer from furnace to water side and causes localised heating; and
   3. mis-aligntment at the nozzle burner which can cause the hot flue gas to converge and concentrate only at certain point or area of the furnace shell.
   Therefore, it is important uphold on safe operating procedure, conduct regular monitoring and to undertake preventive maintenance on steam boiler.
3. The boilerman who is in charge for the operation of the steam boiler should inspect the boiler safety devices like water gauges, mobrey controllers, blowdown valve, burner cut-off, safety valves, feedwater pump, and pressure cut-off switch during the operation of steam boiler and report to their top management of any problem arising.

Figure 1: Low water problem can cause overheating and bulging defect on the furnace shell

Figure 2: Mis-alignment of burner attachment can cause localised overheating  

Figure 3: Formation of layer of scales on the furnace wall at the water side can cause overheating and bulging defect on the furnace shell

Fatal Accident Involving A Passenger Lift

A fatal accident involving a passenger lift happened late 2010 in a low-cost apartment somewhere in the state of Selangor. The victim was found trapped in between the header and lift apron for the lift machine between 5th and 4th floors.Please refer figure 1. This accident caused severe injury which lead to the death of the victim at the scene. Investigation found that the lift was stuck between the levels 6 and 5 or 5 and 4 with 2 passengers inside the lift car. According to witnesses, the victim tried to open the lift landing door in order to rescue the 2 passengers who were trapped inside the lift car. However, the lift car suddenly moved causing the victim to be trapped when the victim tried to climb into the lift car.

 

Figure 1 : Location where victim was found trapped

Recommendation for Safe Action:

1. The passengers inside the lift car which malfuntions should press the emergency button to sound the alarm and not to try to open the lift car.They should wait for the arrival of the lift maintanence company personnel that will render assistance and to get them out of the lift car safely.
2. The public should not attempt to rescue victims trapped in the lift car. Only lift competent person and technicians who are trained and experienced are allowed to undertake such rescue.
3. Maintainence company shall ensure that the lift landing door lock fixture is in good condition and cannot be opened by using any other tool other than the lift door key supplied by the manufacturer. The building owner is not allowed to possess a landing door key without the written permission of the department.
4. Data error log for the control panel in the lift motor room shall be examined and conducted regularly by a competent person. Repair work has to be carried out on all the safety devices for the lift machine that had been identified to be faulty.
5. Lift owner must provide a complete and practical emergency action plan to undertake the safe rescue of the persons trapped inside the lift car.

Marine Piling Barge Accident

 

Figure 1: Accident involving Piling Barge and Transportation Barge 

 

Figure 2: Sketching drawing before accident

 

Figure 3: Sketching drawing  after accident

An accident occured on Jun 2011 involving a self-propelled piling barge at a private jetty located in Port Klang,Selangor. The accident caused serious injury to one worker who later died at the hospital while another three workers were treated with minor injuries. Those workers were working or on the top deck of the self-propelled transportation barge which was docked in front of the piling barge.

The piling barge which was sent back from the piling work in Malacca had undergone maintenance and servicing on the hydraulic cylinders for the luffing winches [on the port and starboard sides]. On completion of the work,the workers were instructed to carry out functional testing on the luffing winches for the luffing mast frame.The luffing mast structure was connected by pendant roping to the A-frame structure which has a tall vertical piling leader attached at its end.

According to the workers the test had been conducted for 4 times.In the midst of the testing one of the luffing winch drums [on the starboard side] suddenly failed and the wire rope layers on the drum uncoiled until its terminal connection.The terminal connection broke off completely from the cap-screw joints which was on the inside of the drum. The failure of the starboard luffing drum mechanism ultimately led to the complete collapse of the luffing mast frame, A-frame structure and the piling leader.During the incident the transporation barge which was docked in front was hit when the structures fell on its top deck.

Investigations found that there were severe damages on the main structure of the luffing winch, luffing mast frame, A-frame and piling leader. Also, the starboard luffing winch rope measuring 38 mm in diameter had completely unwound from the drum and had broken in about three places throughout its length.

The synchronous luffing winch system for the piling barge uses one length of wirerope and the wirerope terminates on the winches. Each of the winch system uses two hydraulic cylinders to control the braking system.

Recommended Control Measure

• The owner or occupier of the piling barge must ensure that Safe Operating Procedures [SOP] for the maintenance works and functional testing on the piling barge were prepared, documented and explained clearly to the workers.
• Secure safely all tall moving parts of the piling barge that have high centre of gravity to avoid any mishap during the maintenance work.
• Permit-To-Work (PTW) must be prepared, issued and followed before commencing any maintenance work on the piling barge. The PTW must include Hazard Indentification, Risk Analysis and Risk Control [HIRARC] or Job Safety Analysis [JSA] on the specific job to be performed. The PTW must ensure so far as practicable, the safety, health and welfare of the workers, public and those who may affected by the job.
• All the inspection, adjustment, repair and maintenance works on the piling barge mechanism should be carried out under the supervision of a competent person. The workers who are undertaking such work need to be trained and have relevant experience and skills to carry out such work safely.
• Any repair or maintenance work on the piling barge should follow published International Code Of Practices or Guidelines.
• Testing of the piling barge structures and mechanism shall not be conducted in poor weather conditions.
• The owner of the jetty shall have control of the works undertaken in his area to ensure that the place of works are safe and without risk to health.