Facility Hazard Index

The sum of UPI and of UHI values for a group of V units (e.g. the units in a facility or vehicle) is used to calculate respectively the overall potential index PI) and the overall hazard index HI) ... 

Table 5.8 shows what a typical worksheet might look like for a laboratory that handles hazardous gases. Note that this worksheet includes a position for the facility risk index. As you can see, if the control is implemented, then the FRI changes. Again, it is very important to include verification of control. This is what ensures that your control is adequate to control the hazard, and it is something that can be verified to be in place. 

A hazards survey can be as simple as an inventory of hazardous materials in a facility or as complicated as a rigorous procedure such as the Dow Fire and Explosion Index (F EI)2 and the... 

Low-hazard waste Any nonexempt waste that is generally acceptable for disposal in dedicated nearsurface facility for hazardous wastes 1 Based on a risk index less than unity for all hazardous substances and assumption that risk or dose to hypothetical inadvertent intruder at disposal site should not exceed acceptable (barely tolerable) levels ... 

Given the assumed types of disposal systems (near-surface facilities or geologic repositories), waste would be classified as exempt, low-hazard, or high-hazard based on the magnitude of its risk index,... 

Use of the risk index in classifying waste is illustrated in Figure 6.2. Classification of waste essentially is a two-step process. The first step involves a determination of whether a waste can be classified as exempt, based on an assumed negligible risk and an exposure scenario for inadvertent intruders appropriate to disposal of waste in a municipal/industrial landfill for nonhazardous waste. If the waste is not exempt, the second step involves a determination of whether a waste can be classified as low-hazard, based on an assumed acceptable (barely tolerable) risk and an exposure scenario for inadvertent intruders appropriate to disposal in a dedicated nearsurface facility for hazardous wastes. 

Given the assumption that an acceptable stochastic risk from disposal in a hazardous waste facility is about 10 3 (see Table 7.1), the stochastic risk index due to the presence of radionuclides in the electric arc furnace waste is (2.5 X 10 5)/10 3 = 0.025. Since this result is much less than unity, the waste clearly would be classified as low-hazard due only to the presence of 137Cs, and there is no need to perform a less conservative analysis. 

As an alternative to the assumption of a one-time exposure for 1,000 h at the time of facility closure, permanent occupancy of a disposal site following loss of institutional control could be assumed (see Section 7.1.3.4). The assumption of chronic lifetime exposure would affect the analysis for hazardous chemicals that induce deterministic effects only if estimated intakes due to additional pathways, such as consumption of contaminated vegetables or other foodstuffs produced on the site, were significant. Based on the results for lead in Table 7.8, an intake rate from additional pathways of about 50 percent of the assumed intake rate by soil ingestion, inhalation, and dermal absorption would be sufficient to increase the deterministic risk index above unity. The importance of additional pathways was not investigated in this analysis, but they clearly would warrant consideration. The increase in exposure time during permanent occupancy does not otherwise affect the analysis for chemicals that induce deterministic effects, provided RfDs are appropriate for chronic exposure, because chronic RfDs incorporate an assumption that the levels of contaminants in body organs relative to the intake rate (dose) are at steady state. 

The index was originally developed for plants where flammable or reactive materials are stored, handled or processed. Yet it may also be used in analyzing the loss potential of sewage treating facilities, distribution systems, pipelines, rectifiers, transformers, boilers, thermal oxidizers and certain elements of power plants. The procedure can also be used for risk evaluations of small processes with modest inventories of potentially hazardous materials. Its application to pilot plants is strongly recommended. The procedure can be applied if a minimum of approximately 454 kg (1,000 lb) of a flammable or reactive material is handled. 

Semi-quantitative techniques, consisting of index and matrix methods. Examples are Dow Fire and Explosion Index, Mond Index, and Pipeline Index for risk ranking of different facilities of the same type, and the matrix method for risk ranking of potential hazardous events that a given facility or organization can face. 

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