Er. LIM Say Leong, ABB Pte. Ltd and Member of EESC, Singapore Standards Council 10 July 2014

Transcription

1 Er. LIM Say Leong, ABB Pte. Ltd and Member of EESC, Singapore Standards Council 10 July 2014 Sharing on the minimum electrical safety rules that helps to save lives My intention today Knowing that working with electricity is one of the significant risks within the construction site. I intend to share the required principles and how we make standards and rules that help to ensure that work on or near electrical equipment and systems can be undertaken safely Illustration of standards EESC have developed for products and practice July 11, 2014 Slide 2 1

2 Accident statistics 95 out of every 100 accidents are the fault of the person involved in the incident Unsafe acts cause more accidents & injuries than unsafe conditions Unsafe conditions 5% 95% Unsafe acts July 11, 2014 Slide 3 Unsafe acts Typically, Not wearing or securing safety belt whilst working at height Not wearing PPE s Wearing inappropriate PPE s Unsafe act is a conduct (whether witnessed or not) that unnecessarily increases the likelihood of injury, violates established safety rules or is contrary to expected conduct Employees unsafe acts show poor safety attitudes and indicate a lack of proper safety training July 11, 2014 Slide 4 2

3 Unsafe Conditions An unsafe condition is a condition, not directly caused by the action or inaction of one or more employees in an area that may lead to an incident or injury if uncorrected. It may be caused by fault design, incorrect fabrication or construction, or inadequate maintenance and subsequent deterioration. The key point that differentiates unsafe conditions from unsafe acts is that unsafe conditions are normally beyond the direct control of employees in the area where the condition is observed. July 11, 2014 Slide 5 When accident happens People look for things to blame when an accident happens, because it is easier than looking for the Root Causes or the Real Problem July 11, 2014 Slide 6 3

4 What do you think cause accident to happen? Carelessness Misuse Getting in a hurry Unsafe acts We know what and how to do but intentionally do something unsafe. We don t know the way to do July 11, 2014 Slide 7 Singapore Standards Council Electrical and Electronic Standards Committee (EESC) Supports the electrical and electronics industry harmonisation of standards standardisation of equipment, systems and installations July 11, 2014 Slide 8 4

5 Product standard for safety RCCB an electro-mechanical device that protects person and animal from electric shock SS 97 deviates from IEC to suit local environment and behavior We have to determine what is safe and applicable in Singapore July 11, 2014 Slide 9 SS CP 88:Part 1:2001 July 11, 2014 Slide 10 5

6 Not just safety at work, home too Let s make safety our way of life Either nothing happens or when it is a closed loop: electric shock burns arc blasts explosion fire falls. July 11, 2014 Slide 11 Don t take your body to test electricity Know the impedance of your body July 11, 2014 Slide 12 6

7 Type of electric shock Direct contact Electric shock in normal service Indirect contact Electric shock in case of a fault L1 L2 L3 N PE L3 N PE July 11, 2014 Slide 13 Effects of 50/60Hz current to the human body IEC Perception threshold -let-go -threshold - fibrillation threshold AC-4 zone: Possibility of irreversible effects AC-4-1 zone: Up to 5% probability of heart fibrillation AC-4-2 zone: Up to 50% probability of heart fibrillation AC-4-3 zone: More than 50% probability of heart fibrillation duration t (ms) Zone no reaction 0,1 0,2 0, reaction, but usually no dangerous effects muscle reaction, breathing difficulties increased probability of heart failure ma 7

8 Ventricular fibrillation T-wave (10-20% of 1 cardiac cycle) Vunerable period (approx. 160 ms) 1 cardiac (heart) cycle (approx. 800ms) July 11, 2014 Slide 15 Arc flash boundary Typical burnt areas on our body The energy received from an arc flash depends on the: Voltage of the arc Length of arc Magnitude of current in the arc Duration of the arc Distance from the arc. 40% of electric accidents relate to an arc flash July 11, 2014 Slide 16 8

9 What happens with the short-circuit When the arc flashes occur 1,200 km/h 300,000 km/s Visible UV 12,000 C (approx 22,000 o F, can go up to 35,000 o F) 165 db 1,000 C < 1,200 km/h 1 kg/cm² IR < 1,000 C 50 cal/cm2 July 11, 2014 Slide 17 Burn injury fundamentals Normal skin 32.5 C Skin burn > 44 C 72 C Burn depth is a measure of severity First degree burn outer skin layer (sunburn, no blister) Second degree burn Middle skin layer (blisters, skin can regenerate) Third degree burns Deep skin layer (grey skin, charred, no skin regeneration possible) 9

10 Step-by-step to safety The seven steps that save lives A video produced by ABB to give an introduction to the ABB "global" safety rules, the effect of human factors on behavior and the minimum required PPE Around the world, ABB work on systems at all voltages. The situations are different, the arrangements with customers are different, the procedures and terminology are different. The 7 steps represent basic principles that must be achieved by ABB's electrical safety system. The 7 steps are based on industry best practice, EN standards, and consultation within ABB. Available from ABB July 11, 2014 Slide 19 The seven steps that save lives 1. Clearly identify work location. 2. Disconnect completely, secure against re-connection. 3. Provide protection against live parts. 4. Take special precautions when close to bare conductors. 5. Verify the installation is dead. 6. Carry out earthing and short circuiting. 7. Issue a permit-to-work. 10

11 Electricity Act - Singapore Permit to work (PTW) ABB 7 steps 1.Clearly identify work location. 2.Disconnect completely, secure against reconnection. 3.Provide protection against live parts. 4.Take special precautions when close to bare conductors. 5.Verify the installation is dead. 6.Carry out earthing and short circuiting. 7.Issue a permit-towork. PTW is issued by a LEW holds the responsibility and authority firsts makes the work safe Following a sequence of procedures stipulated that every part of such apparatus on which work is to be carried out must be: switched off and dead; isolated and lock from live conductors; discharged and effectively earthed; effectively screened off from all live parts to prevent danger; post warning notices; each competent person involved in the work has read, understood and sign all copies of the P-T-W issued by him. Keeping of PTW He/she keeps a copy of the PTW and the keys of all safety lock shall be kept him/her whilst the work is carried out. Completion of work Having confirmed that the work is complete and that others have been warned that they may no longer safely work on the installation in question; the qualified engineer then signs the copy to cancel the permit by specifying the date and time of cancellation. July 11, 2014 Slide 21 And remember Power systems contain enormous amounts of energy Around the world we all work may work on different voltage and practices We must actively manage the risks We must employ systems which take into account human factors One such system is described by the principles of the 7 Steps Everyone in the organisation has a part to play 11

12 WORKING SAFELY BRINGS EVERY ONE JOY, BUT THE MOST IMPORTANT IS FOR YOURSELF AND THE ONES WHO ARE WAITING FOR YOU AT HOME 12