Natech Damage

Besides natech information in the form of natech records, RAPID-N also allows natech damage data to be stored in the database as natech damage records. Natech damage records include information on the extent and characteristics of damage and the number and properties of affected (damaged and undam-aged) plant units. This information can be used to calculate descriptive statistics to support the con-struction of custom fragility curves.

The data fields of the natech damage records are listed in Table 1.

Table 1. Natech Damage data fields

For entering a natech damage record, first the natech that resulted in damage should be selected from the natechs available in the database. Then, the type of the plant units for which damage data will be entered should be indicated. According to the indicated plant unit type, the system lists compatible damage classifications and corresponding damage states that can be used to describe the extent of damage. In order to complete the damage record, the total number of damaged and undamaged proc-ess units should be indicated. Only the number of damaged units is mandatory (Figure 1). If exact numbers are not available, fuzzy numbers can be used to give the best estimates.

The approach used by RAPID-N to collect natech damage information is not based on individual plant units, but on groups of plant units having similar plant unit and damage characteristics. Therefore, common characteristics of the plant units should be indicated by entering appropriate plant unit property values. Similar to other records types, property values can be specified either as fuzzy numbers with units or by selecting suitable option from the provided drop-down lists. Multiple values of a single property can be entered to define a wide range of plant units. For example, the storage conditions can be indicated both as atmospheric and pressurized by adding the storage condition property twice to the list of plant unit properties. In this case, damaged and undamaged values reflect the total number of plant units with atmospheric and pressurized storage conditions. Similar to plant unit proper-ties, damage properties can also be specified to describe the extent of damage and consequences, such as quantity of substance involved in the natech event, hole dimensions, release duration, and pool area. Damage properties can be used to estimate the conditional probability of release and fire events and fine-tuning risk states used for risk assessment.

Bibliographic references, which include information on the damaged plant units, can be indicated. At least one reference is mandatory to assure data quality. Case-specific notes can be specified. Natech damage records can be queried by natural hazard type, plant unit type, and damage classification. A sample natech damage record information page is shown in Figure 1.