Good practice hazards

Laboratoiy procedures may need to be evaluated against the sampling techniques and materials involved in the toll. There may be new laboratoiy chemicals and hazards to be considered. This work may have been identified in the evaluation of special analytical techniques required for the process. A good practice is to ensure that the lab technicians have the necessaiy guidance and types of equipment on hand to monitor the process and waste streams accurately and safely. 

All hoses should be inspected and tested regularly and marked to show that they have been approved for use. A good practice is to change the color of the label every 6 or 12 months. This incident is a good illustration of the way both operators and managers become so used to the hazards of process materials that they fail to establish and maintain proper precautions. How often had the wrong... 

Management must modify the culture and develop human factors awareness in the hazard identification teams so that they will be capable of identifying the potential for human error. A good practice is to involve operators in the hazard identification team. 

A note on good practice. The use of mean bond enthalpies is hazardous because actual bond enthalpies often differ considerably from mean values. The modem procedure for estimating a reaction enthalpy is to use commercial software to calculate the enthalpies of formation of the reactants and products and then to take the difference, as in Section 6.18. 

From 6 April 2005, the Control of Substances Hazardous to Health Regulation 2002 has been significantly updated. There is now a new focus on good practice to help employers prevent their employees health being harmed by workplace chemicals, and a change to the way limits are set for exposure to chemicals in the workplace. An outline of the updated regulations is given. 

Through a survey of select small, medium, and large companies, information was gathered about good practices for reactive hazard management within the chemical industry. CSB also visited chemical industry facilities that have implemented programs for managing reactive hazards. 

Current good practice guidelines on how to effectively manage reactive hazards throughout the life cycle16 of a chemical manufacturing process are neither complete nor sufficiently explicit. 

Section 6.0 and Appendix D discuss good practices and guidelines for reactive hazard management. 

Good practice guidelines illustrate how these parameters are typically examined for both normal and postulated abnormal conditions, such as variations in reactant quantity, concentration, agitation, sequence, time, failure of utilities, and instrumentation. Qualitative hazard evaluation protocols are not well suited for such complex chemical phenomena (e.g., the severity of an uncontrolled reaction under a loss of electrical power may not be apparent without sufficient test data). 

The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a survey of companies that store, handle, and process chemicals. The objective of the survey was to examine current management practices with regard to reactive hazard management. Survey responses served primarily to highlight good practices, but also to point out areas for potential improvement. The survey questionnaire is posted on the CSB website at http //www.chemsafetv.gov/info/Reactives.Survev.Final.pdf. 

There are extensive writings on reactive hazard management. The term guidelines is used herein to refer to good practices that are nonmandatory and are developed through industry consortia, committees, professional societies, and other bodies. 

The purpose of this guidebook, written by Barton and Rogers for the Institution of Chemical Engineers (IChemE), is to provide a basis for good practice in assessing reactive hazards. It is written for those responsible for design and operation of chemical plants. It addresses hazards from uncontrolled exothermic activity in batch and semibatch chemical reaction systems as well as associated process equipment. 

Checklists may also be used to supplement other tools for example, checklists on human factors may be used in conjunction with logic trees. Similarly, checklists may be used in combination with structured brainstorming tools such as What If/Checklist and Hazard and Operability (HAZOP) Analysis.(P It is also a good practice to apply a tool like the 5-Whys to the root causes identified from the checklist to verify whether they are truly root causes. 

An indication of the hazard associated with the use of a toxic material in the form of a vapour or dispersed dust is given by a limit value. The threshold limit value (TLV, expressed as p.p.m. or mg m-3) represents a level under which it is believed nearly all workers may be repeatedly exposed to on a day-to-day basis without adverse effect. These values are up-dated annually and recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).12 Since 1984, in the UK, the Health and Safety Executive (HSE) has adopted two types of limits, but only for those compounds which are available and used in the UK.13 These are the recommended limit (RL, as p.p.m. or mg m 3) which represents good practice and realistic levels for the degree of exposure, and the control limit (CL, as p.p.m. or mg m 3) which is applied to the relatively smaller number of substances having unusually serious toxic effects. 

Any chemistry laboratory is a place that has many sources of hazards, including explosive, toxic or flammable chemicals, noxious vapors, broken glass, and hot liquids and solids. In addition to the rules given below, good practice requires that the instructor and student review each experiment for all potential hazards and discuss steps to avoid or mitigate such hazards. The review should include considerations of dangerous chemicals and conditions in each experiment. 

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