Controlled safety

The basic approach is to direct the system to the safest operating level relative to people or the environment when any emergency condition is detected, including power loss. An important concept of process control safety is to have adequate redundancy to reduce unwanted shutdowns and maintain an adequate level of certainty that a safe state will result if a real emergency does occur. As far as possible, instruments should be of the fail-safe type. 

Ozonation systems are comprised of four main parts, including a gas-preparation unit, an electrical power unit, an ozone generator, and a contactor which includes an off-gas treatment stage. Ancillary equipment includes instruments and controls, safety equipment and equipment housing, and structural supports. The four major components of the ozonation process are illustrated in Figure 8. 

All controls, safety devices and items required for the proper operation of the flare. 

Active—Using controls, safety interlocks, and emergency shutdown systems to detect and correct process deviations e.g., a pump that is shut off by a high level switch in the downstream tank when the tank is 90% full. These systems are commonly referred to as engineering controls. 

Thus the maximum flow in a pipe occurs when the velocity at the exit becomes sonic. The sonic location may be other than the exit, can be at restrictive points in the system, or at control/safety relief valves. 

Active controls use engineering controls, safety interlocks and emergency shutdown systems to detect process deviations and take appropriate corrective or remedial action. Their effectiveness depends on proper selection, installation, testing, and maintenance. 

Fire protection system impairment occurs when a fire alarm or supervisory system is shut-off, damaged, fails, or is otherwise taken out-of-service completely or in part. These out-of-service conditions are called impairments. While process monitoring, control, safety, and security-entry systems also provide protective functions, this element of the fire prevention program is only concerned with impairments to fire protection systems and equipment. An essential element of the fire prevention program is a procedure for fire protection impairment handling. 

Physical data can provide a source of valuable information for investigators. Investigators should not only consider the process system itself, but also control, safety, support, auxiliary, and adjacent systems as part of the analysis. When examining physical data, typical items of interest include ... 

Safety and environmental factors—absence of, or controllable, negative impacts, no current and pending negative regulations, reliable plans to control safety and environmental problems. 

Cornish, J.W. et al., A randomized, double-blind, placebo-controlled safety study of high-dose dextromethorphan in methadone-maintained male inpatients, Drug Alcohol Depend., 67, 177, 2002. 

Dyker A. G. and Lees K. R. (1999). Remacemide hydrochloride a double-blind, placebo-controlled, safety and tolerability study in patients with acute ischemic stroke. Stroke 30 1796-1801. 

Active—Control or mitigate incidents using controls, safety interlocks, or emergency shutdown systems to detect hazardous conditions and take appropriate action to place the plant in a safe condition. 

Gather the requirements for the systems including functional (e.g. operational checks) requirements, nonfunctional (e.g., coding standards) requirements, users, company-wide regulatory compliance (e.g., Part 11 technical control), safety, process, and other applicable requirements Characterize information, assess its value to the organization, and incorporate information quality as part of the project plan Conduct a system (hardware, software, and process) risk analysis. New requirements may be found as the result of the risk analysis. Any new requirements must be documented in the requirements specification deliverable... 

EN 4126 Part 5 = Controlled Safety Pressure Relief Systems (CSPRS)... 

Power actuated/assisted safety valves (CSPRS - controlled safety pressure relief system) A spring-operated safety valve actuated or assisted by an externally powered control device which can be hydraulic, pneumatic or electric (Figure 3.15). 

The controlled safety pressure relief system (CSPRS) (Figure 5.31) is a special type of actuated SRV that has mainly been used in Europe and in power applications, primarily in the German power industry, for the last 40 years. So far, it has not been used extensively in other parts of the world, but it has become more important since it has its own EN/ISO 4126 Part 5 code in the new European regulation. 

CEN - European Committee for Standardization Brussels wvwv.cenorm.be EN/ISO 4126- Safety Devices for Protection Against Excessive Pressure Part 1 - Safety Valves Part 2 - Bursting Disc Safety Devices Part 3 - Safety Valves and Bursting Disc Safety Devices in Combination Part 4 - Pilot Operated Safety Valves Part 5 - Controlled Safety Pressure Relief Systems Part 6 - Application, Selection and Installation of Bursting Disc Safety Devices Part 7 - Common Data... 

IAEA (1988). International Atomic Energy Agency. Principles for the Exemption of Radiation Sources and Practices from Regulatory Control, Safety Series No. 89 (International Atomic Energy Agency, Vienna). 

Lew MF, Adornato BT, Duane DD, Dykstra DD, Factor SA et al. (1997) Botulinum toxin type B a double-blind, placebo-controlled, safety and efficacy study in cervical dystonia. Neurology 49 701-7... 

Control objectives for a chemical process originate from certain regulation tasks (i.e. product quality control, material balance control, safety, environmental regulations, etc.) and economic objectives (i.e. optimizing the economic performance). Such a classification of control objectives automatically formulates the different design activities for the regulatory and optimizing control structures. 

International International Conference on Releases guidelines for quality control, safety testing, www.pharmweb.nt/pwmirror /... 

---