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This paper contains the results of investigations concerning electrical safety related to the effects of industrial frequency currents passing through the human body. Results of experimental research into ventricular fibrillation conducted on animals for 50 Hz currents of short duration (in the range of 0.1 to 3 s) are presented. Recommendations concerning maximum permissible 50 Hz currents for humans are given, which are included in GOST 12.1.038–82 “Occupational Standards Safety System; Electric Safety; Maximum Permissible Levels of Touch Voltages and Currents.”

A lower bound, depending upon a restricted virtual displacement system, is found for the volume of material required by thin shells, which carry given loads, including hydrostatic pressure, to given supports. The loads are carried by membrane stress-resultants and Tresca’s safety criterion is satisfied. Sufficient conditions for the attainment of the bound lead to optimum designs in some simple cases, namely those for which the optimum structure is indeed a thin shell and not a three-dimentional continuum.

Electromagnetic fields (EMFs) are the relatively new, but rapidly intensifying ecologic factors. For millions of years the biological life on the Earth has been developing and undergoing evolution under influence of complex natural EMFs generated by the external sun radiation and natural electric fields in the atmosphere. The exposure was relatively weak, as the natural EMF intensities does not exceed the order of 10-8–10-9 W/m2. The situation has changed however dramatically some 50 years ago with introduction of various devices generating microwaves (MWs) and radiofrequencies (RFs) first for communication and navigation and later for multiple industrial and household purposes. The steady increasing occupational groups and whole populations of people living in certain areas (e.g., close to power lines and stations, TV/Radio broadcasting antennas, air force bases,etc.) are continously being exposed to EMF intensities that by few magnitude orders exceed the natural fields of the Earth. At present only the second-third generation of human beings is exposed to artificially generated EMFs and the long-term effects of these exposures are still difficult for forecasting. Despite numerous experimental investigations and epidemiologic studies, it is still not possible to prove the existence and character of any specific molecular, cellular or system-related damage that may be evoked by long-term exposure in low-level EMFs.

In 1985 San Francisco adopted a wind ordinance as part of its Downtown Plan. To our knowledge, it is the first U.S. wind code containing specific legal and technical requirements for compliance. It addresses both comfort and safety criteria. The comfort criteria tend tobe the critical ones in San Francisco's unusual climate, where uncomfortable sea breezes are pervasive but dangerously strong winds relatively rare. Compared to the criteria used in other codes worldwide, this ordinance uses relatively low threshold windspeeds that may be exceeded relatively large amounts of the time. This paper discusses the development of the ordinance and its compliance guidelines by which wind testing procedures and reporting are standardized. A critical part of the effort was obtaining and generalizing an appropriate wind record for the downtown area. This is discussed, together with considerations for achieving uniformity among consultants' reports.

The use of formal decision models can supposedly enhance the quality of safety decisions. It is discussed why there has been an increasing demand for such models in recent years. A short description of a safety model is presented. This model is based on the basic ideas of formal decision analysis and it has been applied in many different fields of technology.

As part of an Army-wide expansion and modernizing program, the safe separation distance for production of 155mm M795 HE projectiles was studied, tested and determined in a series of tests. The test results were used to establish safety criteria for new manufacturing Load-Assemble-Pack (LAP) facilities and also minimum nonpropagation distance was drafted by ARRADCOM and was subsequently conducted in two separate phases. The exploratory phase consisted of ten separate tests utilizing one donor projectile and two acceptor projectiles. The confirmatory test phase consisted of 25 tests involving 50 acceptors (25 donors), with the spacing distance held constant. Test results indicated that a safe spacing distance of 4.57 meters (15.0 feet) was appropriate.

The safety standards for environmental and occupational exposure to electromagnetic fields (EMFs) being accepted and operating in Eastern European countries, members of the Council for Mutual Economic Assistance (Comecon), and in the USSR follow since their establishment a different philosophy, as compared to the standards and rationales introduced in the USA and Western European countries.

This report presents results from a General Atomic Company alternate design study for the core auxiliary cooling system (CACS) of the 300-MW(e) Gas-Cooled Fast Reactor (GCFR) Demonstration Plant. The purpose of this study was to evaluate CACS design concepts similar to that used in the large High-Temperature Gas-Cooled Reactor (HTGR), which has a non-boiling core auxiliary heat exchanger (CAHE) and CACS startup from rest. The study considers current 1977 safety criteria and requirements and includes design, transient analysis, drive and control trade-off studies, and analysis methods development. Transient analysis of the revised CACS design indicates satisfactory core cooling for all required operating conditions, according to current criteria.

This report describes the activities of DOD personnel, both military and civilian, in Shot PRISCILLA, the 5th nuclear test in the PLUMBBOB atmospheric weapons testing series. The test was conducted on 24 June 1957 and involved participants from Exercise Desert Rock VII and VIII, and AEC test groups. This volume also describes the radiological safety criteria and procedures in effect at Shot PRISCILLA. (Author)

Two strawman designs have been devised to aid in the development of analytical techniques for evaluating advanced solar cell encapsulation systems designs. The optical model for a multi-layer system in which reflection, absorption, and transmission may occur between layers, was completed and analytically verified. An expression giving the electrical safety criteria for a multi-layer dielectric system has been derived. A thermal analytical analysis program has been developed which will accommodate up to six different material layers for the determination of NOCT. MSC/NASTRAN has been selected as the primary structural analysis computer code. A matrix of materials and properties has been prepared. Work has begun in finding the necessary material properties.

The Reliability Approach to Structural Safety is discussed, including the development of quantitative criteria for evaluating and substantiating the safety of structural systems under various load environments.

A betavoltaic device, the Betacel ® Model 400 L battery has been developed specifically for use in cardiac pacemakers. This paper discusses standards for design of environmentally qualified nuclear batteries and examines how effectively these are achieved in the betavoltaic device.

The Energetic Systems Process Division, LCWSL, is engaged in the development of safety criteria in support of LAP(Load-Assembly-Pack) facilities as part of the overall modernization and expansion of LAP manufacturing explosive facilities. One of these criteria is the safe separation distance between 155 mm HE projectiles as they are transported along the production line. Testing of this projectile to determine the minimum nonpropagation distance between donor and acceptor units was started at Yuma Proving Ground, with follow-up test carried out at the National Space Technology Laboratories and Hawthorn Army Ammunition Plant. Phase I consisted of a series of exploratory tests to In Phase 2 an empty projectile was used as a shield halfway between the donor unit and each acceptor unit. Phase 3 consisted of a series of tests to determine the safe separation distance between projectiles that would not provide nonpropagation of a detonation and would not allow adjacent projectiles to contaminate the immediate area with scattered and armed grenades.

The Oak Ridge National Laboratory has three multipurpose research reactors which accommodate testing loops, target irradiations, and beam-type experiments. Since the experiments must share common or similar facilities and utilities, be designed and fabricated by the same groups, and meet the same safety criteria, certain standards for these have been developed. These standards deal only with those properties from which safety and economy of time and money can be maximized and do not relate to the intent of the experiment or quality of the data obtained. The necessity for, and the limitations of, the standards are discussed; and a compilation of general standards is included.

Publisher Summary This chapter provides an overview of power plant siting. The location of a nuclear plant contributes to the safety of the operation and determines to what extent such a plant is considered safe by outsiders. Safety is defined in three ways: (1) the risk of damage to the integrity of the system from any cause, (2) the risk of harm to operating personnel from normal or abnormal functioning of the plant, and (3) the risk or hazard from any cause, mechanical, biological, or radioactive, to the surrounding population. The first two safety criteria are usually met by suitable plant design and layout and are affected by the selected site only insofar as unfavorable geological or meteorological phenomena—earthquakes, subsiding ground, flooding, or high winds—might interfere with the proper functioning of the facility. It is the third criterion that is uppermost in the mind of most intervenors and the general public when they raise objections to the location of a nuclear plant in a given locality. All of these are covered by the requirement that they must lead to activity levels that are as low as practicable, which, in practice, may be interpreted as levels below 1% of maximum permissible levels.

The paper presents an original method of soil analysis using elasto plastic finite elements. The method is a deterministic approach of the fatigue problems which consist in correlating cyclic laboratory test results with magnitude and duration of wave loadings. The loadings used for the soil analysis are determined by a separate statistical study. The analysis presented aims at a sound evaluation of the safety criteria of gravity platform foundations taking into account the fatigue effects.

In order to provide the scientific community, as well as NASA management, with a preview of typical safety restrictions for the proposed Black Brant XII sounding rocket, a risk assessment for a typical payload has been performed. This paper details the considerations which ensure minimal risk for projects managed by Wallops Flight Facility and the safety criteria required to conduct an operation. Specifically, three launch scenarios for the Black Brant XII have been considered. The first case assumes a test launch from Wallops, and the other two cases analyze typical scientific missions from Poker Flat Research Range.

This report describes the activities of an estimated 10,600 DOD personnel, both military and civilian in Operation TUMBLER-SNAPPER, the third nuclear weapons testing series conducted at the Nevada Proving Ground. TUMBLER- SNAPPER consisted of eight nuclear tests conducted from 1 April to 5 June 1952. Activities engaging DOD personnel included Exercise Desert Rock IV programs, scientific experiments, and DOD support activities. Radiological safety criteria and procedures were established and implemented during Operation TUMBLER-SNAPPER to minimize participants' exposure to radioactivity.

Recent policies of the Bureau of Radiological Health of the Food and Drug Administration on the manufacture and use of laser equipment for light shows are summarized. Specific points covered include determination that laser light shows are products subject to the Radiation Control for Health and Safety Act of 1968, reporting and variance requirements, and criteria for safe design and operation of a laser light show.

Safety criteria are developed for intended or expected electrical shocks based on a comparison of the electric shock outputs to levels considered non-hazardous, such as that from an electric fence controller or from a continuous 6 mA, 60 Hz shock. The true r.m.s. value of the current for a periodic pulse type shock cannot always be compared to the effect of the same 60 Hz r.m.s. current because higher frequency components of the pulse output have a lesser effect on the human body. Periodic pulse type shocks are evaluated by obtaining an effective value for the current taking into account the attenuation of the effect of frequency components above 1 kHz on the human body.

Recent developments in the use of liquid fluorine as a fuel for space vehicles has created a requirement to establish safety criteria which will eliminate potential hazards in the plumbing systems and holding tanks. An area of extreme potential hazard is the use of porous Teflon gaskets which contain organic solvents. When Teflon is processed through cleaning cycles containing trichloroethylene, the Teflon can absorb a sufficient quantity of solvent to cause incompatibility with liquid fluorine, creating a violent reaction.

Publisher Summary This chapter discusses the status of technology of large, fast nuclear reactors in the mid-1960's, exemplified by description of a design approach using the state-of-the-art technology. The approach has been to update a previous study with respect to safety criteria and operating limits for fuel, cladding, and coolant in the light of present knowledge. Within these bounds, a preliminary reference reactor core, coolant system, and containment design have been selected, based on parametric studies. Once the design was established, hazard analyses were performed to predict the dynamic response of the reactor and plant to credible plant accidents. The hazards analyses were extended to include the severe accidents, which are deemed “hypothetical” because of the chain of improbable events required. A reactor containment concept was designed and an analysis was made to prove its adequacy for the hypothetical accident event. The plant economics were estimated, with emphasis on the effect of the safety assumptions on the fuel cycle costs. The possible effect on fuel cycle costs of physics data uncertainties and changes in fuel performance limits were determined. The approach taken is conditioned by analysis of safety considerations affecting design. The selection of conservative safety criteria continues to be a fundamental question, not only of technology, but also of policy.

Subsequent to the recent formulation and adoption of safety criteria for reactor cooling systems, there appeared the need for an independent evaluation of the safety and reliability of the K-Reactor cooling system in terms of these criteria. The primary, secondary and last-ditch cooling systems of this reactor involve a strong inter-dependence between electrical and hydraulic components of the water plant. Because of the complexity of inter-relationships between these components, the analysis was divided into two parallel studies which were accomplished during the simmer of 1959. F. D. Robbins has presented his analysis of the electrical power and control system in HW-61887. This report deals with an engineering analysis of the hydraulic and mechanical aspects of the reliability and safety of the K-Reactor Cooling System. The system, as described in this report, is that which existed during the simmer of 1959, prior to modification under Project CG-775 (now Project CG-883).

Specification of fuel damage criteria is important in evaluating and verifying the adequacy of safety margins for the FFTF. These margins are provided to meet the established safety objectives for the facility. The purpose of this report is to review the parameter limits specified as preliminary design data in the FFTF design safety criteria, and to identify the bases for each of these limit values. These bases provide a logical framework for discussion of the uncertainties involved as well as emphasize the more promising options for maximizing the return on investment of development funds.

A series of biomedical experiments using chemical lasers was performed in the Aerodynamics and Propulsion Research Laboratory. The purpose of the tests was to establish safety criteria for Air Force-operated laser systems in the 2.6- to 4-micrometer wavelength range. Threshold damage levels were determined for minimal visual corneal damage to the rhesus monkey eye from radiation emanating from HF and DF chemical lasers operating in both continuous and pulsed modes. These are the first corneal damage threshold data obtained at these wavelengths.

The initial fuel landing for the N-Reactor and the use of a specific alternative fuel element are described in a previous report. It is highly probable that it will also be desirable in the future to irradiate still other types of fuel elements in the reactor. If the test is of small scale, fever than five channels, or if these elements vary only slightly from the initial fuel load (or any other fuel type approved for large-scale use at some future date), the irradiation will be accomplished within the normal administrative procedures and controls established for the Production Testing Program. In this context, in-reactor testing of minor changes in the fuel cladding alloy, alternate methods of affixing end closures, different fuel support designs or similar changes are considered to be within the scope of normal productiontesting. It is possible, however, that it will be desirable to irradiate test fuel elements which are significantly different from any element approved for general use and in quantities of greater than five fuel columns at a given time. A more formalized review of such tests including approval by the AEC would appear appropriate in these instances. The purpose of this document is to outlinemore » criteria which can be usedto judge the stability of all such tests from the standpoint of reactor nuclear safety. It is intended that these criteria apply to test fuel loadings comprising up to 50 fuel columns within the reactor at a given time.« less

This project has sought to develop greater understanding of the interaction of explosive blast forces with the structural targets which require protection from the accidental detonation of stored explosives. The relationships which have been developed will be helpful in understanding the risks which are implied in the established explosive quantity-distance criteria and will provide a basis for estimating the potential damage to structures exposed in a blast field which is sufficient to cause incipient structural failure. This study has been implemented through the definition of ten specific structures which have been "exposed" to the blast forces from five charge sizes through analytical modeling techniques. All charges considered have been spherical, surface burst, bare TNT. The charges considered were limited to the following five sizes: 1,000, 10,000, 100,000, 1,000,000, and 9,000,000 pounds.

Preliminary engineering studies have indicated the need for modifications and improvements to the reactor coolant backup systems of the old areas in order to provide adequate safety of operation at power levels programmed for the future. These evaluations of the coolant backup systems were based on the recently adopted reactor cooling safety criteria. It was concluded that the secondary coolant systems would be adequate in capacity and reliability for the proposed future operating conditions except for certain cases of natural disaster such as earthquake damage. It was concluded that the last ditch coolant systems would be inadequate for the proposed future reactor operating conditions. The purpose of this report is to define the scope of modifications and improvements required to provide adequate last ditch systems in the old areas for future operating conditions as proposed by the Reactor Modification Program. Irradiation Processing Department, Fiscal Years 1961 through 1966. Adequate last ditch cooling will be provided for the 100-K Areas under Project CGI-844 which is currently in progress. The results of this study provide a basis for future budgeting action and project planning.

This work introduces a preliminary study on upcoming driver assistance systems based on Optimal Control. Systems of this kind are intended to monitor driver-vehicle behavior and environmental surroundings in order to warn the driver of possible dangerous situations, and work by constantly comparing the real vehicle maneuver to a recommended reference maneuver planned by optimal control. The latter (the optimal control reference maneuver) is based on safety criteria, in which a proper "risk function" is minimized. In this paper the case of "safe speed" is preliminarily addressed. The influence of different risk function formulations (for safe speed) on system performance is investigated. Simulations are carried out for a vehicle running along a S-shaped curve at constant speed, and the driving advices resulting from safe-optimal reference maneuvers are analyzed.

In this paper, we study the safety guarantees of group communication-based database replication techniques. We show that there is a model mismatch between group communication and database, and because of this, classical group communication systems cannot be used to build 2-safe database replication. We propose a new group communication primitive called \emph{end-to-end atomic broadcast} that solves the problem, i.e., can be used to implement 2-safe database replication. We also introduce a new safety criterion, called \emph{group-safety}, that has advantages both over 1-safety and 2-safety. Experimental results show the gain of efficiency of group-safety over lazy replication, which ensures only 1-safety.

A new bullnose guardrail system for the treatment of median hazards was developed and successfully crash tested according to the safety criteria set forth in NCHRP Report 350. The new system consists of a nose section 4500 mm wide by 4824 mm long, comprising three sections of curved thrie beam guardrail attached to parallel sides of thrie beam guardrail 4500 mm apart. The nose section was designed to safely capture and contain vehicles impacting the nose. Two 6 × 25 steel cables were attached behind the top two humps of the nose section to ensure vehicle capture in the event the thrie beam ruptured. Additionally, the first five sections of guardrail had horizontal slots cut in the valleys of the rail to improve vehicle capture and reduce the formation of large kinks that could pose a threat to a vehicle as the system deformed to absorb an impact. The research study included computer simulation modeling using LS-DYNA and full-scale vehicle testing using 2000-kg pickup trucks and 820-kg small cars in accordance with the Test Level 3 safety performance requirementd specified in NCHRP Report 350. Nine full-scale crash tests were performed on the new system. Several changes were made to the bullnose system to improve its safety performance during the course of the testing and development.

To test whether vaginal delivery after cesarean section (VDAC) is a safe alternative to repeated section, a retrospective chart review of 2,350 deliveries during a ten-year period in a private practice group committed to VDAC was studied. Eighty-five parturients met six predetermined safety criteria and were permitted a trial of labor. These criteria were (1) prior low-segment transverse uterine incision; (2) vertex presentation; (3) carefully monitored labor with obstetrician present; (4) availability of emergency facilities; (5) no administration of oxytocin; and (6) patients' consent and desire to pursue VDAC. Seventy-six labors (89%) managed expectantly were successful in VDAC. No maternal or fetal morbidity was detected. No uterine ruptures were detected on postpartum examination or at the time of cesarean section. These results support the 1980 report of the National Institute of Child Health and Human Development recommending that labor and VDAC are of low risk to mother and fetus in properly selected cases. ( JAMA 1983;249:2935-2937)

(1985). A Review of: “Safety of dams: flood and earthquake criteria” Committee on safety criteria for dams for the National Research Council of the United States National Academy Press, Washington, D.C., USA, 1985, 276 pp, £18.50. Civil Engineering Systems: Vol. 2, No. 4, pp. 232-233.

Although national and international standards regarding laser safety either already exist or are in the course of preparation, they do not specifically cover the use of lasers in optical fibre transmission systems.It is necessary to relate the safety requirements for lasers as published in the national and international standards to optical sources as used in optical fibre transmission systems. This paper attempts to do this and to stimulate discussion of the problems involved. The paper concludes that under normal operation optical fibre systems are intrinsically safe, since no exposure to optical radiation is possible. In cases where a fibre end is exposed, minimum viewing distances are proposed.

There is now considerable interest around the world in developing scientifically based safety limits for medical ultrasound, especially as applied in diagnosis. While there has been no evidence of harm caused by past exposures to diagnostic ultrasound, some of the newer applications employ higher intensities than were used formerly. Hence, there is need for quantitative information on acoustic conditions that pose different degrees of risk, to guide manufacturers, users, and regulators. It is fairly generally agreed that a promising way to generate such information is to consider the separate biophysical mechanisms by which ultrasound can cause biological damage. This special session is to deal with research findings that relate to these mechanisms, and their relevance to safety limits.

It has been known for decades that ultrasound is capable of producing physiological change in man and in laboratory animals. A dominant mechanism for the change is temperature elevation resulting from sound absorption. It has been shown for some situations that the processes for heat generation and transport are understood well enough to make it feasible to predict the temperature that results from specific acoustic exposures. Thus Pond, Robinson and Lele, Carstensen, Lizzi, and others have successfully calculated intensity‐time combinations required for production of recognizable lesions in mammalian tissues and other media. There is now special interest in computational methods for application to ultrasonic hyperthermia, and also to the formulation of safety criteria for diagnostic ultrasound. For the latter purpose a simplified method has been developed, based on a Green's function solution to the bio‐heat transfer equation. In this paper, previous work on temperature calculations is reviewed, and recent results discussed.

The paper describes the design of a fail-safe sensor used for the detection of the speed of a moving railway vehicle. The sensor is required for use in automatically controlled trains that run at one of a number of predetermined speeds, selected with reference to safety criteria, and governed by conditions ahead of the train. The device uses an axle-coupled permanent-magnet a.c. generator that, at the predetermined speed, saturates a transformer with low-frequency current, choking the passage of an audio-frequency signal from a constant-voltage source, and hence cutting off the output. Positive feedback is employed to sharpen the cut-off slope. A computer model based on a sinusoidal analytical method, superimposing the low and audio-frequency signals, predicts the possibility of in stability and hysteresis occuring in the output characteristic under certain conditions. Computed and test results are found to be in good agreement, and a series of circuit-design criteria are derived.