Analyzing the existing hazards in structuring the metal frame of the building with PHA method

Article history: Received April 20, 2012 Accepted 21 July 2012 Available online July 22 2012 Every day in workplaces, continues events occur that cause death and injury. These accidents usually happen because of lack of exploring the potential hazards and lack of training of employees. Hence, with exploring and evaluating the hazards of workplace and utilizing the suitable procedures, it is possible to prevent from many of these hazardous incidents. Exploring, evaluating and controlling the potential hazards have been the initial stages of scientific safety assurance in every system. Preliminary hazard analyzing is the first effort in analyzing hazards. In this method, usual hazards in sighted job are explored, using the usual hazards table for developing the basis of PHA, the PHA checklist is prepared and at last the PHA table completed and the appropriate suggestions are given. In this paper, we present an implementation of PHA method in one of industries located in city of Tehran, Iran. The proposed study uses 15 explored hazards, where 2 are unacceptable, 9 are undesirable and 4 are acceptable with need of revisal. By eliminating and reducing each hazards risk, some controlling solutions are suggested. The most important of these solutions are utilizing and using the regulations of the welding with electrical archer. © 2012 Growing Science Ltd. All rights reserved.


Introduction
A risk assessment is an important step to protect workers and businesses, as well as complying with laws and regulations.It helps to focus on important risk factors, which influence workplaces and can potentially create some injuries.In many instances, suitable measures can readily control risks, for example, we must make sure that spillages are cleaned up promptly so people do not slip, or cupboard drawers are kept closed to ensure people do not trip.The law does not expect us to eliminate all risk factors, but we are required to protect people as far as 'reasonably practicable'.This is not the only way to do a risk assessment, there are other methods that can work well, particularly for more complex risks and circumstances.However, we believe this method is the most suitable for most organizations.A risk assessment is simply a careful examination of what could cause injury in our work, so that we could weigh up whether we have taken enough precautions or should do more to prevent harm.
Workers and others have the right to be protected from harm caused by a failure to take reasonable control measures.Accidents and illness can ruin lives and affect business too if output is lost, machinery is damaged, insurance costs increase or have to go to court.We are legally required to assess the risks in our workplace so that we implement a plan to control the risks (Glade, 2004;Nasiri et al., 2006).Welders are working in the widespread kinds of industries and working in each of these environments has its own problems.Structuring the metal frame of the buildings with use of electrical archer welders is one of the welders work basis, in addition to continuous hazards that congenitally exists in process.Because of implementing the job in hard situations like working in places with high height, probability of accidents is increasing (Kolverzi, 2009).From the researches, Ingredients that cause the accident in welding are:  20% insufficient experiment  10% incapability  70% not following safety recognitions With spotting the above numbers, we can find out the necessity of training, culturizing and obeying laws and safety recognitions in welding.It is expecting that this paper could help through the culturize for safety society (Kolverzi, 2009).

Research framework and methodology
Today, there is a steady increase in using the methods of risk assessment in different industries.There are over 100 kinds of quantity and quality analyzing methods, where each of these methods has specific theory canton, advantages and disadvantages.Major of risk analyzing methods are suitable hazard analyzing methods and their results can be used for management and decision making in controlling and reducing events.In most of these kinds of analyzing methods, the appropriate methods are chosen based on some necessary goals (Coutu et al., 2012).These techniques have known as different names such as HAZOP, FM & EA, BT & EA, and PHA (Arghami & Pouya, 2006) and can be used in different stages such as planning, producing, maintenance, etc. (Menson,2004).Preliminary hazard analysis (PHA) is the first effort in exploring hazards, which is a procedure for detecting hazards and the most important and the first safety comparison examination that starts with exploring and analyzing the hazards (Sadeghi, 2006).The best time to implement PHA is in planning and manufacturing system (Evans, 2006).Results from PHA can sighted as risk control by management (Leggett, 2012).In this research, we propose a method for risk assessment using some tools like checklists, matrixes, descriptions, instruments dissection, events report, surveying information and similar occupations, review of last reports, talking to the contractors and manufacturers (Table 1).After completing usual hazard table, preliminarily hazard list is provided and the causes and effects in hazardous situations are characterized.Also for determining the risk priority according to hazards and developing a criterion for decision making, list of hazard intensity (Table 2), hazard possibility (Table 3), and risk evaluation matrix (Table 4) are evaluated.Next, based on the information of hazard intensity, possibility and risk evaluation matrix, PHA are completed and suggestions are given to prevent, to control or to reduce possible hazards.

Analyzing the suggested method
All hazards and possible hazardous events must be identified and it is important to consider all parts of any system, operational modes, maintenance operations, safety systems, and so on.All findings should be recorded and unimportant hazards must be ignored.Murthy's law must be borne in mind: "If something can go wrong, sooner or later it will" (Park, 2008).Preliminary hazard analysis (PHA) is a semi-quantitative analysis that is performed to: -Identify all potential hazards and hazardous events that may lead to an accident, -Rank the identified hazardous events according to their severity, -Identify required hazard controls and follow-up actions.
The PHA should consider hazardous components, safety related interfaces among various system elements, including software, environmental constraints including operating environments, operating, test, maintenance, built-in-tests, diagnostics, and emergency procedures, facilities, real property installed equipment, support equipment, and training, safety related equipment, safeguards, and possible alternate approaches, malfunctions to the system, subsystems, or software (Pompa, 2009).

PHA prerequisites
3.1.1.Establish the PHA team 3.1.2.Define and describe the system to be analyzed -System boundaries (which parts should be included and which should not) -System description; including layout drawings, process flow diagrams, block diagrams, etc.
-Use and storage of energy and hazardous materials in the system -Operational and environmental conditions to be considered -Systems for detection and control of hazards and hazardous events, emergency systems, and mitigation actions 3.1.3.Collect risk information from previous and similar systems (e.g., from accident data bases)

PHA team
A typical PHA team may consist of: -A team leader (facilitator) with competence and experience in the method to be used -A secretary who will report the results Team members (2-6 people) who can provide necessary knowledge and experience on the system need to be analyzed.Some team members may participate only in parts of the analysis.

3.3.System functions
As part of the system familiarization it is important to consider: -What is the system dependent upon (inputs)?-What activities are performed by the system (functions)?-What services does the system provide (output)?

3.4.System breakdown
To be able to identify all hazards and events, it is often necessary to split the system into manageable parts, for example, in three categories: -System parts (e.g., process units) -Activities -Exposed to risk (who, what are exposed?)

Process explanation
Electro current engenders from streaming electrons in ductile path.Because of different voltage and existing current, the air (gas) between the two ductile materials become ionized and the current in between establishes, the electrical archer happens.This is used as thermal recourse in welding.In this case, electrode fuses and causes the conjunction of two materials.In some points that welders cut out weld dust with hammer or other instruments, eye injury hazard with D probability, 2 intensity and 2D risk evaluation exists.In order to prevent these injuries employees must use eye glasses with crystal shields to reduce risk evaluation to 4E.Moving and anagrammatizing tools and heavy things, doing repetitive work, work on bad situations and keeping long time instruments can cause bone illnesses, muscles, back ache, shoulders ache, reduction of muscle power, whitening fingers, knee illnesses, etc.The risk associated with these issues could be reduced from 3C to 4D by observing ergonomic points.Existence of flammable and combustible substances near welding place or around it can cause resources firing and instruments or even individual's injury.Therefore, with 3 intensity, C probability and 3C risk evaluation, the risk can be reduced to acceptable 3E by observing regulations and welding and cutting work laws and instructions.There are 2 kinds of sting rays, one is acute visible light and the others are UV and IR, the first one, with 2D risk level, can cause eye pain, cataract, scalding cornea, tearing and retina injury and the best way to reduce this risk item is to 4E, which is using welding masks.Old electricity generators always have sound pollution, which cause combination of ear, sibilating ear, down falling hearing, nerve provocation, stupefaction, etc.This risk item can be reduced from 3D to 4D by isolating sound resources, increasing sound source distance from people, using earmuffs or ear pluck.
Other injuries include bruises, leg injury, fracturing categorized in 3E risk level, which could happen because of falling down materials, cornerstone, headrester, etc.It is possible to use of safety shoes and to increase attention at work in an attempt to upgrade safety level to 4E.The risk of 3E level could happen because of device short circuit, overworking, overloading the device, over heating the device.It is also possible to upgrade the risk to 4E by continues measurement of device heat, putting device in suitable place, capsules being available

Table 1
Usual hazards group

Table 7 )
is organized according to the points given in PHL table(Table 6) related to risk levels and pursuit priority of 3 levels of unacceptable, undesirable and acceptable in need of reconsideration.By giving controlling suggestions, risk level has reached to acceptable level by reconsideration and without reconsideration.Baseless to this table down falling hazard had intensity number 2 and probability level B with risk evaluation 2B,with using safety belts and training work laws, it's risk level became 4B or acceptable.But with financial supports and facilities it can be reduce to lower levels.Hazards associated with electricity shock such as contacting to conductor, humidity, having contact with gadget and welding device that caused electric shock, scalding, down falling and even death accidents can be reduce from unacceptable levels like 2B, 1C, 2C to acceptable levels like 4B, 3E, 3D, 2E.This could happen with observing regulations and welding instructions, training, using standard instruments, and self protection devices.When there are some hot devices such as weld outlets, remaining of electrode's bottoms or working materials, employees may face a chance of having unexpected fire incidents, which could harm them, severely.This hazard with 3 intensity, probability on C and risk evaluation 3C can be reduced to acceptable level 4D with using leather clothes or other adamant materials versus heat or fire.Fumes with 3C risk level cause breathing and pulmonary disease like coughing lung inflation and asthma, which could reduce to 4C with observance to safety notes and using suitable masks.