Danger, defined

This classification system allocates to substances a number between 0 (minimum danger) and 4 (maximum danger) defined by NFPA as follows ... 

With regard to inflammability, NFPA coding classifies reactivity hazard into five degrees from 0 (no danger) to 4 (maximum danger), defined as follows ... 

In the investigations described above, the measurements have been interpreted in terms of the parameters of a well-defined flux model. However, it is appropriate at this point to illustrate the dangers of an imprecise... 

Inhalation. The threshold limit value of HCN is 4.7 ppm. This is defined as the maximum average safe exposure limit for a 15-min period by the Occupational Safety and Health Administration. Exposure to 20 ppm of HCN in air causes slight warning symptoms after several hours 50 ppm causes disturbances within an hour 100 ppm is dangerous for exposures of 30 to 60 min and 300 ppm can be rapidly fatal unless prompt, effective first aid is adininistered. There is always a small concentration of cyanide (0.02 to 0.04 mg/L) in the blood, and the body has a mechanism for continuous removal of small amounts, such as from smoking, by converting it to thiocyanate, which is discharged in the urine. 

Subsection B This subsection contains rules pertaining to the methods of fabrication of pressure vessels. Part UW is applicable to welded vessels. Service restric tions are defined. Lethal service is for lethal substances, which are defined as poisonous gases or liquids of such a nature that a very small amount of the gas or the vapor of the liquid mixed or unmixed with air is dangerous to life when inhaled. It is stated that it is the user s responsibility to advise the designer or manufacturer if the service is lethal. All vessels in lethal service shall have all butt-welded joints fully radiographed, and when practical, joints shall be butt-welded. All vessels fabricated of carbon or low-aUoy steel shall be postweld-heat-treated. 

DANGEROUS SUBSTANCES (uk) Defined substances which may be hazardous to the fire services in an emergency. (Dangerous Substances (Notification and Marking of Sites) Regulations 1990.)... 

Defined substances over which control is exercised for conveyance in all road tankers or in tank containers >3 m capacity. (The Carriage of Dangerous Goods by Road Regulations 1996.)... 

Defined substances covered by a comprehensive system to inform consumers of potential dangers and to reduce the hazard when carried by road. The Chemical (Hazard Information and Packaging for Supply Regulations 1994). 

Healtli issues, most importantly, conttuninants in tlie workplace, have become OSHA s primary concern. Healtli haztu-ds are comple.v and difficult to define. Because of this, OSHA has been slow to implement healtli standards. To be complete, each standard requires medical surveillance, record keeping, monitoring, and physical reviews. On the other side of the ledger, safety hazards are aspects of the work environment tliat are e. pected to cause deatli or serious physical harm immediately or before tlie imminence of such danger can be eliminated. 

Hazard, risk, failure, and reliability are interrelated concepts concerned witli uncertain events and tlierefore amenable to quantitative measurement via probability. "Hazard" is defined as a potentially dangerous event. For example, tlie release of toxic fumes, a power outage, or pump failure. Actualization of the potential danger represented by a hazard results in undesirable consequences associated with risk. 

Requirements for labelling of containers for supply may differ from those for conveyance. Key features of a supply label are to identify the substance (the chemical name in most cases) and any hazards and safety precuations. In Europe the classification, packaging and labelling of dangerous substances is covered by Directive 67/548/EEC as amended. This requires labels to identify appropriate risk and safety phrases (Tables 12.2 and 12.3) depending upon product properties. A substance is considered dangerous if in Part lA of an approved list or if it exhibits hazardous properties as defined in Schedule 1 for supply, or Schedule 2 for conveyance as shown in Tables 12.4 and 12.5. Substances not tested should be labelled Caution — substance not yet fully tested . Criteria for risk phrases are provided, e.g. as in Table 12.6 for toxic compounds. 

Determine whether it is a dangerous substance as defined. If so, classify it from the Approved List or from Schedule 1. 

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