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Submitted to instructor, Dessalegn A
Submission date 22 DEC 2016
Assignment of waste water treatment and air pollution Control
I
TITLE: HAZARDOUS IDENTIFICATION
GROUP MEMBERS
Name Id No
1. Tamirat Assefa__________________________________T00025/06
2. Mulugeta Faye_________________________________01639/05
3. Tarik Seged_____________________________________01921/05
4. Yemisrach Z/gebrieal___________________________02124/05
5. SimegnAsrat ___________________________________01845/05
6. Danayit Nega___________________________________00931/05
7. Sintayehu Chemeda_____________________________01854/05
8. Teferi Poulos_____________________________________01941/05
9. Belete Maru______________________________________01266/04
10. Aytenaw Asrie__________________________________01205/04
11. Yosef Woretaw__________________________________01036/05
12. Amare Habtamu________________________________00686/05
13. Getahun Tarekegn________________________________01924/04
14. Nahom Dalei_____________________________________00819/05
15. Damesa Angasa__________________________________00930/05
16. Amanuel Abera__________________________________00671/05
17. Hussen Fedelu____________________________________01324/05
18. Maleda Maekos___________________________________01456/05
Assignment of waste water treatment and air pollution Control
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Table of Contents Page CHAPTER FOUR ......................................................................................................................................... 1
4.1. HAZARDOUS IDENTIFICATION ...................................................................................................... 1
4.1.1 Risk: ............................................................................................................................................. 1
4.1.2 Risk assessment: .......................................................................................................................... 2
4.1.3 Risk control: ................................................................................................................................. 2
4.2 PROCESS HAZARD CHECKLIST ................................................................................................... 5
4.2.2 General work environment ........................................................................................................... 6
4.2.3 Personal protective equipment ..................................................................................................... 7
4.2.4 Walkways ..................................................................................................................................... 8
4.2.4 Floor and wall stairways .............................................................................................................. 9
4.3. HAZARDS SURVEYS ..................................................................................................................... 9
4.3.1 Identify and Describe the Facility .............................................................................................. 10
4.3.2 Identify Generic Emergency Conditions .................................................................................... 11
4.4. HAZARD AND OPERABILITY (HAZOP) STUDIES .................................................................. 12
4.5. SAFETY REVIEW .......................................................................................................................... 14
REFERENCE ............................................................................................................................................ 16
Assignment of waste water treatment and air pollution Control
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CHAPTER FOUR
4.1. HAZARDOUS IDENTIFICATION
Hazard identification (HAZID) is “the process of identifying hazards, which forms the essential
first step of a risk assessment. There are two possible purposes in identifying hazards:
To obtain a list of hazards for subsequent evaluation using other risk assessment
techniques. This is sometimes known as “failure case selection”.
To perform a qualitative evaluation of the significance of the hazards and the measures
for reducing the risks from them. This is sometimes known as “hazard assessment”.
During the hazard identification stage, the criteria used for the screening of the hazards will be
established and possible hazards and accidents will be reviewed. For this purpose, the facility
will be divided into several sections. Furthermore, the identified hazards will be classified into
critical and non-critical hazards. It is of great importance that the hazards considered non-critical
are clearly documented in order to demonstrate that the events in question could be safely
disregarded.
Hazard Identification: This is the process of examining each work area and work task for the
purpose of identifying all the hazards which are “inherent in the job”. Work areas include but are
not limited to machine workshops, laboratories, office areas, agricultural and horticultural
environments, stores and transport, maintenance and grounds, reprographics, and lecture theatres
and teaching spaces. Tasks can include (but may not be limited to) using screen based
equipment, audio and visual equipment, industrial equipment, hazardous substances and/or
teaching/dealing with people, driving a vehicle, dealing with emergency situations, construction.
This process is about finding what could cause harm in work task or area.
4.1.1 Risk:
The likelihood, or possibility, that harms (injury, illness, death, damage etc) may occur from
exposure to a hazard.
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4.1.2 Risk assessment:
Risk assessment is defined as the process of assessing the risks associated with each of the
hazard identified, so the nature of the risk can be understood. This includes the nature of the
harm that may result from the hazard, the severity of that harm and the likelihood of this
occurring.
4.1.3 Risk control:
Taking actions to eliminate health and safety risks so far as is reasonably practicable. Where
risks cannot be eliminated, then implementation of control measures is required to minimize
risks so far as is reasonably practicable.
The most important step in managing risks involves eliminating them so far as is reasonably
practicable, or if that is not possible, minimizing the risks so far as is reasonably practicable. In
deciding how to control risks you must consult your workers and their representatives who will
be directly affected by this decision. Their experience will help you choose appropriate control
measures and their involvement will increase the level of acceptance of any changes that may be
needed to the way they do their job. There are many ways to control risks. Some control
measures are more effective than others.
You must consider various control options and choose the control that most effectively
eliminates the hazard or minimizes the risk in the circumstances. This may involve a single
control measure or a combination of different controls that together provide the highest level of
protection that is reasonably practicable. Some problems can be fixed easily and should be done
straight away, while others will need more effort and planning to resolve. Of those requiring
more effort, you should priorities areas for action, focusing first on those hazards with the
highest level of risk.
The hierarchy of risk control
The ways of controlling risks are ranked from the highest level of protection and reliability to the
lowest as shown below. This ranking is known as the hierarchy of risk control. The
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HIGHEST MOST
LOWEST LEAST
Figure 2: The hierarchy of risk control
Level 1: Control Measures – Eliminate the Hazard
The most effective control measures eliminate the hazard and associated risks. This can be
achieved through removing the hazard or selecting alternate products or equipment to eliminate
the risk. If a hazard cannot be eliminated then risks can be minimized by lower control measures
Level 1
Eliminate the hazards
Level 2
Substitute the hazard with something safer
Isolate the hazard from people
Reduce the risks through engineering controls
Level 3
Reduce exposure to the hazard using
administrative actions
Use personal protective equipment
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Level 2: Control Measures
These are used to minimize the risks and involve on or a combination of the following;
(i) Substitute the hazard: substitute a substance, method or material to reduce the risk or the
hazard
(ii) Isolate the hazard: separate the hazard from the workplace or people, For example;
a. Chemical store room, or a laboratory kept locked except to an authorized person.
b. Lock out procedures on faulty equipment.
c. Appropriate guarding for machinery.
(iii) Use engineering controls: modify existing machinery or plant or purchase different
machinery or plant to provide a physical solution. For example;
a. Trolleys, hoists or cranes.
b. Guard rails.
Level 3: Control Measures
These are control options which should be considered last as they do not control the source of the
hazard but rely on human behavior or supervision and are therefore less effective. They include;
(iv) Administrative Procedures: develop work methods or procedures to reduce the conditions
of risk, for example:
a. Written Safe Operating Procedures
b. Job rotation to restrict hours worked on difficult jobs.
c. Staff trained in the correct operating procedures.
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(v) Use Personal Protective Equipment (PPE) and training in its use:
Offer the lowest level of protection and should only be used as a last resort to deal with the
hazard, where the hazard cannot be removed or reduced by any other means, for example:
a. Handling of chemicals – gloves, safety glasses, aprons.
b. Protecting eyes from flying particles.
c. Protecting feet – safety boots.
Consultation with workers is required in the selection and implementation of control measure in
the workplace. Controls may need to be trial led to determine effectiveness and workers should
be involved in the feedback process.
Each measure must have a designated person and date assigned for the implementation of
controls. This ensures that all required safety measures will be completed and documented.
Monitoring and review: This involves ongoing monitoring of the hazards identified, risks
assessed and risk control processes and reviewing them to make sure they are working
effectively.
4.2 PROCESS HAZARD CHECKLIST
Process hazard checklistgives general guidance to the person conducting a business or
undertaking (PCBU) about possible workplace health and safety hazards and issues. It is not
intended to be exhaustive, nor will every item relate to every workplace. You should conduct
risk assessments for work tasks and manage the risks you find. You must also ensure licensing
and registrations are maintained as required by law.
The following checklist can be used to identify and evaluate hazards in your workplace. This
checklist covers a wide variety of workplace safety and health hazards. All of the topics covered
in this checklist may not apply to your particular workplace. When evaluating your workplace
use the sections of the checklist that apply to your workplace and work activities.
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4.2.2 General work environment
Are all worksites clean and orderly?
Are work surfaces kept dry or appropriate means taken to assure the surfaces are slip-
resistant?
Are all spilled materials or liquids cleaned up immediately?
Is combustible scrap, debris and waste stored safely and removed from the worksite
promptly?
Is accumulated combustible dust routinely removed from elevated surfaces, including the
overhead structure of buildings?
Is combustible dust cleaned up with a vacuum system to prevent the dust going into
suspension?
Is metallic or conductive dust prevented from entering or accumulation on or around
electrical enclosures or equipment?
Are covered metal waste cans used for oily and paint-soaked waste?
Are all oil and gas fired devices equipped with flame failure controls that will prevent
flow of fuel if pilots or main burners are not working?
Are paint spray booths, dip tanks and the like cleaned regularly?
Are the minimum number of toilets and washing facilities provided?
Are all toilets and washing facilities clean and sanitary?
Are all work areas adequately illuminated?
Are pits and floor openings covered or otherwise guarded?
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4.2.3 Personal protective equipment
Are protective goggles or face shields provided and worn where there is any danger of
flying particles or corrosive materials?
Are approved safety glasses required to be worn at all times in areas where there is a risk
of eye injuries such as punctures, abrasions, contusions or burns?
Are employees who need corrective lenses (glasses or contacts lenses) in working
environments with harmful exposures, required to wear only approved safety glasses,
protective goggles, or use other medically approved precautionary procedures?
Are protective gloves, aprons, shields, or other means provided against cuts, corrosive
liquids and chemicals?
Are hard hats provided and worn where danger of falling objects exists?
Are hard hats inspected periodically for damage to the shell and suspension system?
Is appropriate foot protection required where there is the risk of foot injuries from hot,
corrosive, poisonous substances, falling objects, crushing or penetrating actions?
Are approved respirators provided for regular or emergency use where needed?
Is all protective equipment maintained in a sanitary condition and ready for use?
Do you have eye wash facilities and a quick drench shower within the work area where
employees are exposed to injurious corrosive materials?
Where special equipment is needed for electrical workers, is it available?
When lunches are eaten on the premises, are they eaten in areas where there is no
exposure to toxic materials or other health hazards?
Is protection against the effects of occupational noise exposure provided when sound
levels exceed those of the Cal/OSHA noise standard?
Assignment of waste water treatment and air pollution Control
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4.2.4 Walkways
Are aisles and passageways kept clear?
Are aisles and walkways marked as appropriate?
Are wet surfaces covered with non-slip materials?
Are holes in the floor, sidewalk or other walking surface repaired properly, covered or
otherwise made safe?
Is there safe clearance for walking in aisles where motorized or mechanical handling
equipment is operating?
Are spilled materials cleaned up immediately?
Are materials or equipment stored in such a way that sharp projectiles will not interfere
with the walkway?
Are changes of direction or elevations readily identifiable?
Are aisles or walkways that pass near moving or operating machinery, welding
operations or similar operations arranged so employees will not be subjected to potential
hazards?
Is adequate headroom provided for the entire length of any aisle or walkway?
Are standard guardrails provided wherever aisle or walkway surfaces are elevated more
than 30 inches above any adjacent floor or the ground?
Are bridges provided over conveyors and similar hazards?
Assignment of waste water treatment and air pollution Control
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4.2.4 Floor and wall stairways
Are floor openings guarded by a cover, guardrail, or equivalent on all sides (except at
entrance to stairways or ladders)?
Are toe boards installed around the edges of a permanent floor opening (where persons
may pass below the opening)?
Are skylight screens of such construction and mounting that they will withstand a load of
at least 200 pounds?
Is the glass in windows, doors, glass walls that are subject to human impact, of sufficient
thickness and type for the condition of use?
Are grates or similar type covers over floor openings such as floor drains, of such design
that foot traffic or rolling equipment will not be affected by the grate spacing?
Are unused portions of service pits and pits not actually in use either covered or protected
by guardrails or equivalent?
4.3. HAZARDS SURVEYS
The Hazards Survey is intended to identify emergency management program needs which are
different from those addressed by the Hazards Assessment. Therefore, each facility/site should
be included in a Hazards Survey, regardless of the need for a Hazards Assessment. It is expected
that much of the material necessary to generate a Hazards Survey will already have been
developed in the course of meeting other DOE and Federal agency requirements relating to
facility safety, occupational safety, environmental and effluent controls, and hazardous materials
management. However, the intent of the Order is not likely to be met by simply defining existing
documents or analyses as the Hazards Survey Document. Information, such as facility
descriptions or materials inventories, may be incorporated by reference; hazardous material
inventory information need only be documented to the extent necessary to determine whether
further assessment and planning are required. However, the Hazards Survey Document should be
a distinct document and should contain, or incorporate by reference, the information specified
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herein. To promote efficiency, the Order requires that each Hazards Survey incorporate as many
facilities as possible that are subject to the same type of hazards.
The recommended steps in the Hazards Survey are:
(1) Identify and briefly describe each facility;
(2) Identify the generic emergency conditions that apply to each facility;
(3) Qualitatively describe the potential health, safety, or environmental impacts of the applicable
emergencies; and
(4) Identify the applicable planning and preparedness requirements.
4.3.1 Identify and Describe the Facility
Each facility or activity covered by the Hazards Survey should be identified and a brief
description of its operations provided. Highly specific and detailed information is not necessary
and may be included by reference. However, at a minimum, sufficient information to provide a
general understanding of the facility(ies) covered should be included. Areas to be addressed
include:
A general characterization of the facility and its operations (e.g., office building, laboratory,
warehouse);
The normal occupancy, including the number of people in other than ground floor work
locations;
Whether classified material is used or stored in the facility; !Any special designations, such
as nuclear facility; radiological facility; hazardous waste site; Treatment, Storage, or
Disposal (TSD) facility; etc.; and
Whether hazardous materials (other than standard office products and cleaning supplies) are
used or stored in the facility.
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4.3.2 Identify Generic Emergency Conditions
Identify and document the emergency conditions that may occur at each facility for which some
level of planning and preparedness may be required. Hazardous materials below the screening
thresholds or not specifically addressed as part of the hazardous materials program should be
considered when identifying generic emergency conditions. As a minimum, the following
generic emergency conditions should be considered:
Structure fires;
Natural phenomena impacts (wind, flood, earthquake, wildfire);
Environmental releases (of oil or other pollutants that degrade the environment);
Hazardous material releases;
Malevolent acts (hostage-taking, sabotage, armed assault);
Facility damage with possible compromise of classified material;
Workplace accidents/mass casualty events (explosion, release of toxic fumes, high energy
system failure);
Hazards external to the facility/site (e.g., hazardous materials in near-by facilities,
transportation accidents, accidents involving utilities, etc.); and
Accidental criticality.
Some emergency conditions will apply to nearly every facility (e.g., fires) while others will only
apply to facilities that exceed a threshold inventory (e.g., oil) or are located near other hazards.
Site-specific potential hazards, such as flooding from a nearby dam failure, should be included in
the list of potential emergencies to identify the facilities that are potentially threatened. Federal
Emergency Management Agency (FEMA), National Weather Service (NWS) , and insurance
industry documents are all potential sources of information. The Local Emergency Planning
Committee (LEPC) is a potential source of information in hazards faced by the area.
Hazards originating outside the DOE facility and site that could impact the health and safety of
onsite personnel or other DOE interests should be identified and examined. As a minimum, the
Local Emergency Planning Committee should be consulted to identify nearby facilities having
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hazardous material inventories that could impact the DOE site. Railroads, highways, and other
transportation arteries that pass through or near a DOE facility or site should be considered as
possible locations of hazardous material transportation accidents. If the transportation artery is a
known corridor for a particular hazardous substance, identify the substance, quantities,
approximate shipment frequencies, and Protective Action Zone distance specified in the
Department of Transportation (DOT) emergency response guidebook. Because the chemicals
covered by the DOT Emergency Response Guidebook are limited, distances similar to Protective
Action Zones may need to be calculated for excluded hazardous substances. Once this
information is collected, determine whether specific arrangements should be made for protection
of onsite personnel. As a minimum, identify the transportation arteries as potential sources of a
hazard to onsite personnel.
4.4. HAZARD AND OPERABILITY (HAZOP) STUDIES
A HAZOP study identifies hazards and operability problems. The concept involves investigating
how the plant might deviate from the design intent. If, in the process of identifying problems
during a HAZOP study, a solution becomes apparent, it is recorded as part of the HAZOP result;
however, care must be taken to avoid trying to find solutions which are not so apparent, because
the prime objective for the HAZOP is problem identification. Although the HAZOP study was
developed to supplement experience based practices when a new design or technology is
involved, its use has expanded to almost all phases of a plant’s life. HAZOP is based on the
principle that several experts with different backgrounds can interact and identify more
problems when working together than when working separately and combining their results.
The "Guide-Word" HAZOP is the most well-known of the HAZOPs; however, several
specializations of this basic method have been developed.
The HAZOP concept is to review the plant in a series of meetings, during which a
multidisciplinary team methodically "brainstorms" the plant design, following the structure
provided by the guide words and the team leader's experience.
The primary advantage of this brainstorming is that it stimulates creativity and generates ideas.
This creativity results from the interaction of the team and their diverse backgrounds.
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Consequently the process requires that all team members participate (quantity breeds quality in
this case), and team members must refrain from criticizing each other to the point that
members hesitate to suggest ideas. The team focuses on specific points of the design
(called "study nodes"), one at a time. At each of these study nodes, deviations in the process
parameters are examined using the guide words. The guide words are used to ensure that the
design is explored in every conceivable way. Thus the team must identify a fairly large number
of deviations, each of which must then be considered so that their potential causes and
consequences can be identified. The best time to conduct a HAZOP is when the design is fairly
firm. At this point, the design is well enough defined to allow meaningful answers to the
questions raised in the HAZOP process. Also, at this point it is still possible to change the design
without a major cost. However, HAZOPs can be done at any stage after the design is nearly firm.
For example, many older plants are upgrading their control and instrumentation systems.
The success or failure of the HAZOP depends on several factors:
• The completeness and accuracy of drawings and other data used as a basis for the study
• The technical skills and insights of the team
• The ability of the team to use the approach as an aid to their imagination in visualizing
deviations, causes, and consequences
• The ability of the team to concentrate on the more serious hazards which are identified.
The process is systematic and it is helpful to define the terms that are used:
a. Study nodes - The locations (on piping and instrumentation drawings and procedures)
at which the process parameters are investigated for deviations.
b. Intention - The intention defines how the plant is expected to operate in the absence of
deviations at the study nodes. This can take a number of forms and can either be descriptive or
diagrammatic; e.g., flow sheets, line diagrams, P&IDS.
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c. Deviations- These are departures from the intention which are discovered by systematically
applying the guide words (e.g., "more pressure").
d. Causes- These are the reasons why deviations might occur. Once a deviation has been shown
to have a credible cause, it can be treated as a meaningful deviation. These causes can be
hardware failures, human errors, an unanticipated process state (e.g., change of composition),
external disruptions (e.g., loss of power), etc.
e. Consequences - These are the results of the deviations should they occur (e.g., release
of toxic materials).
Trivial consequences, relative to the study objective, are dropped.
f. Guide words- These are simple words which are used to qualify or quantify the intention in
order to guide and stimulate the brainstorming process and so discover deviations. The guide
words shown in the following table are the ones most often used in a HAZOP; some
organizations have made this list specific to their operations, to guide the team more quickly to
the areas where they have previously found problems. Each guide word is applied to the
process variables at the point in the plant (study node) which is being examined.
4.5. SAFETY REVIEW
The safety review was perhaps the very first hazard analysis procedure developed. It is
commonly used to identify safety problems in laboratory and process areas and to develop
solutions.
There are 2 types of safety reviews: the informal and formal.
The informal safety review is used for:
Small changes to existing processes, and
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Small, bench-scale or laboratory processes
The informal safety review procedure usually involves just 2 or 3 people. It includes the
individual responsible for the process and 1 or 2 others not directly associated with the process
but experienced with proper safety procedures. The idea is to provide a lively dialogue where
ideas can be exchanged and safety improvements developed.
The reviewers simply meet in an informal fashion to examine the process equipment and
operating procedures and to offer suggestions on how safety of the process might be improved.
Significant improvements should be summarized in a memo for others to reference in the future.
The improvements must be implemented before the process is operated.
Example
The formal safety review is used for:
New processes
Substantial changes in existing processes, and
Processes which need an updated review
The formal safety review is a 3-step procedure. This includes:
Preparation of a detailed formal safety review report
Committee review of the report and inspection of the process, and
Implementation of the recommendations
The procedure begins by the preparation of a detailed safety review report. The purpose of this
report is to provide the relevant safety information regarding the process or operation. This
report is generally prepared by the process engineer.
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REFERENCE
1. Barling, J. &Frone, M. (2004) (eds.) The Psychology of Workplace Safety. Washington:
APA
2. Job Hazard Analysis booklet www.osha.gov/Publications/osha3071.pdf
3. Probabilistic Risk Assessment. (Procedures Guide for NASA Managers)
4. www.hq.nasa.gov/office/codeq/doctree/praguide.pdf Books
5. www.npsa.nhs.uk/nrls/improvingpatientsafety/patient-safety-tools
andguidance/rootcauseanalysis/
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