Mechanical and electric locks in access control and management systems: Some issues of developing technical requirements.

Mechanical and electric locks in access control and management systems: Some issues of developing technical requirements.

Mechanical and electric locks in access control and management systems:
Some issues of developing technical requirements

The magazine continues publishing a series of articles on locking devices. This article presents proposals for developing technical requirements for mechanical locks and electric locks for resistance to unauthorized opening and breaking based on an analysis of domestic and foreign standards

With the introduction of GOST R 51241-98 «Access control and management systems and devices. Classification. General technical requirements. Test methods» in 2000, the issue of certification of devices included in access control and management systems (ACM devices), including electric locks as actuators, arises. The article «Electric locks in access control and management systems» (magazine «Security, communication and telecommunication systems», 1999, No. 30) examined the provisions of GOST R 51241 defining the basic requirements for electric locks, and provided characteristics of 3 groups of these locks, namely:
1st group — electromechanical locks (hereinafter — Emn locks). in which the mechanical locking element (bolt) is controlled by the action of electric current from the corresponding electrical components;
2nd group — electromagnetic locks (hereinafter referred to as Emg locks), in which there is no mechanical locking element, and the appearance or removal of the holding force is carried out by an electromagnetic field, respectively, when the supply voltage is applied or switched off;
3rd group — electronic locks (hereinafter referred to as Eel locks), in which the mechanical locking element (bolt) is controlled by the action of electric current from electrical and electronic components that have and create the possibility of expanding functions.

The 1st and 3rd groups of electric locks contain mechanical elements, therefore, when developing requirements for these electric locks, it is necessary to consider the requirements that apply to mechanical locks or their individual elements. The selection of requirements and the establishment of parameters for electric locks should be based on the requirements of GOST R 51241 and a number of domestic standards that affect their characteristics, among which the following should be noted:

GOST 5089-97 Locks and latches for doors. Technical conditions;

GOST 30109-94Protective doors. Test methods for resistance to burglary;

GOST 51053-97 Safe locks. Requirements and test methods for resistance to criminal opening and burglary;

GOST 51072-97Protective doors. General technical requirements and test methods for burglary resistance and bullet resistance. When conducting certification tests of KUD devices, tests for compliance with electrical safety and electromagnetic compatibility requirements are mandatory. Therefore, the following should also be taken into account:

GOST 12.2.006-87 (IEC 65-85) Safety of electronic network equipment and similar devices intended for household and similar general use;

GOST 27570.0-87 (IEC 335-1-76) Safety of household and similar electrical appliances. General requirements and test methods;

GOST R 50009-92Electromagnetic compatibility of technical means of security, fire and security-fire alarm systems. Requirements, standards and methods of testing for noise immunity and industrial radio interference.

Using foreign experience

When developing the standard, it is necessary to use significant foreign experience in creating requirements and testing methods for high-security electric locks, especially for operation in KUD systems. As one of the documents, the provisions of which can be used in developing a domestic standard for electric locks, it is necessary to consider the English version of the European standard Рг EN 1300 «Secure storage modules. Classification of high-security locks according to their resistance to unauthorized opening».

The standard sets requirements for locks in terms of reliability, resistance to burglary and unauthorized opening, and also presents methods and evaluation of test results for these types of impacts. What is especially important is that it applies simultaneously to mechanical and electronic locks. It is advisable to use this approach when developing a similar domestic standard, according to which locks are classified into 4 classes (A, B, C. D, of which A is the lowest) according to the following parameters:

• resistance to manipulation;

• resistance to destructive impacts:

• resistance to electromagnetic interference for electronic locks.

Additionally, electronic locks are classified by the minimum number of codes that can be stored and used for encoding and the maximum number of attempts to guess the code. The maximum number of attempts to guess the code within 1 hour is set only for electronic locks and is 300 attempts for class A, 100 for class B, 30 for class C and 10 for class D.

Table 1. Safety requirements

The main parameters and their values ​​by classes are presented in Tables 1 and 2. Electronic locks are tested for resistance to rapid voltage changes with a rise time of 5 ns. In this case, all classes of locks must function normally at a maximum voltage of 1 kV and must be fail-safe at a maximum voltage of 2 kV for class A and B locks; 4 kV for class CID locks.

Table 2. Minimum requirements for the resistance of electronic locks to electromagnetic interference

The verification of the conformity of locks with the requirements of the standard Pr EN 1300 is carried out according to the test methods established by this standard, and the resistance of electronic locks to electromagnetic interference is verified according to EN 50130-4 and EN 50081-1.

Certain provisions of the Pg EN 1300 standard have already been used in the development of the domestic GOST R 51053 for safe locks. However, the standard for safe locks cannot be fully extended to electric locks due to the difference in their designs and conditions of protection against unauthorized force impacts. Test methods should be significantly changed, especially in the classification of tools, devices and their use during testing.

GOST R 51053 establishes requirements for safe locks (hereinafter referred to as «locks») in terms of resistance to criminal opening and breaking without the use of penetrating radiation, as well as methods for testing them for resistance. The standard does not apply to locks for general-purpose doors, which must also be taken into account when developing a standard for electric locks of KUD systems. The most comprehensive requirements are contained in the American National Standard ANSI/LJL 1034-1995 «Burn-Resistant Electric Locking Mechanisms». The first edition of the standard was adopted back in 1975, and the main provisions are set out according to the fourth edition of 1995, taking into account the amendments made in 1997. The requirements apply to an electric locking mechanism (hereinafter referred to as «ELM») with burglary protection, intended for use in conjunction with an access control system or a manual unlocking mechanism. They are based on the results of research, test registration, installation and operation experience and represent the basis for the creation of a domestic standard. The requirements relate to the design, characteristics and operation of electronic electronic machines with burglar protection and to the devices associated with them (control units, control switches and power supplies), as well as to similar devices used to unlock doors.

The design requirements ensure:

•electrical safety;

• corrosion protection;

• methods of making internal electrical connections;

• protection against excessive currents;

• design of individual elements, such as switches, transformers, etc.

The characteristics of electronic electronic machines are divided into three groups:

1. Characteristics applicable to all devices. This group includes characteristics that ensure the operability of all devices in specified operating modes, operating conditions, as well as electrical and fire safety. The standard sets out in sufficient detail the requirements for electrical protection provided by: the design of the housing, casing of the product and their elements, the sizes of permissible gaps or openings in them, the choice of materials and methods of their insulation, the possibility of safe access for service personnel.

2. Characteristics applicable to outdoor equipment. This group includes characteristics that ensure the operability of outdoor devices under conditions of exposure to salt spray, rain, and dust. When setting out the requirements for corrosion protection, attention is drawn to the need for galvanic compatibility of metals used in housings and casings.

3. Characteristics of the EBM resistance to certain unauthorized actions that are most significant for the domestic standard. They include characteristics that ensure the resistance of the EBM to the impact of external forces, including using a tool to press on the structure, by determining residual magnetism. It is according to the characteristics of the 3rd group, which determine the effectiveness of EBM with protection against burglary, that they are classified. These characteristics include durability and resistance to static and dynamic loads.

The standard establishes:

• durability of 100,000 or 250,000 cycles;

• static loads of 500 pounds (2,224 I), 100 pounds (4,448 N) or 1,500 pounds (6,673 N);

•dynamic loads of 33 ft-lbs (45 J), 50 ft-lbs (68 J) or 70 ft-lbs (95 J).

For all the characteristics stated, test methods and evaluation of their results are given. All tests are carried out on ordinary doors made of solid wood with a thickness of 38-44 mm, a width of 0.91 m and a height of 1.8-2.1 m. The door is installed in a frame made of sheet steel mounted in a brick wall or in a rigid steel frame attached to the floor and fixed on the side that corresponds to the inside of the door. The door must be hung on 3 heavy-duty hinges.

Normal operation tests consist of checking the ability of the electronic control module to perform its target functions at specified nominal values ​​of voltage, current, and power. Input and output parameters are checked within the permissible deviations from the nominal voltage, as well as from the backup power supply, if provided. In this case, the battery must be fully charged to ensure operation for 4 hours with the locking mechanism triggered every 5 minutes.

During overload tests, the electronic control module must perform its functions during and after 50 triggering cycles at a triggering frequency of 17 cycles per minute and connected to a power source with the maximum permissible voltage from the nominal voltage (in this standard, -115%). The sequence of operations in each triggering cycle includes:

• unlocking the locking mechanism;

•opening the door;

•closing the door;

• engaging the locking mechanism.

A similar sequence of operations is used during durability testing.

The force tests, i.e. static and dynamic resistance, shall be carried out by means of impacts or forces applied to the door at a distance of 40 inches (1 m) from the bottom edge of the door and 6 inches (152 mm) from the edge opposite to that on which the door suspension hinges are located. It is important to state the requirements and methods of testing for resistance of EBM to tool impact and voltage surges, and for EMG locks to residual magnetism.

Tool Impact Test

The tamper-resistant electric locking mechanism shall first be positioned in the test fixture before an attempt is made to open the lock. This shall be carried out for 5 minutes by an operator familiar with the mechanism. The method of action used shall be determined by the design of the mechanism, which cannot be accessed by physical force. The means used for the tool action test shall be small enough to be carried in a pocket. They shall include blade and Phillips-head screwdrivers, wire, hooks and similar devices no longer than 8 inches (203 mm), and ordinary open-end wrenches no larger than 0.5 inches (12.7 mm). During the attempt to open the lock, the locking mechanism shall not be damaged to such an extent that it cannot perform its essential functions after the attempt to open has ceased.

Residual Magnetism Tests

The electromagnetic lock shall be mounted properly in the locked position on the test fixture and connected to a power source of rated voltage. Power shall be supplied to the electromagnetic lock for 24 hours with the lock in the locked position and the electromagnetic in contact with the armature. After 24 hours, the power source shall be disconnected and the force required to open the door shall be measured. It shall open with a force of 4 pounds (18 N) or less.

Surge Testing

A product that uses electronic components, transistors, silicon controlled valves (SCU), integrated circuits and similar devices must operate, ensuring its basic characteristics, after exposure to:

• 500 surges of line supply voltage;

• 500 internal surges;

• 60 surges in input/output circuits when the product is operated from a power source that meets the requirements of the standard.

At the end of the test, the device must meet the requirements set out in section «Tests for normal operation». The standard DIN 18103-92 «Burglar-resistant doors. Terms, technical requirements and marking» should also be considered as influencing the establishment of requirements for locks. The standard establishes requirements for locking devices that must ensure the resistance of doors to burglary according to resistance classes (see Table 3.)

Table 3. Door resistance indicators by resistance classes

The bolts of the main lock and additional (if any) must enter the door frame socket to a depth of at least 15 mm. In the GOST R system, as noted above, there are two standards that affect the establishment of requirements for mechanical locks and electric locks.

The first domestic standard establishing requirements for the resistance of doors and locks to burglary is GOST 30109, which defines the requirements and methods for testing doors with locking mechanisms for resistance to static and dynamic loads: it applies to wooden external and internal entrance doors from stairwells to apartments, to public, industrial, auxiliary buildings and structures.

The standard establishes 5 categories of strength for burglary resistance, the main characteristics of which are given in Table 4. Due to the widespread use of metal doors, categories 4 and 5 can be used to assess the strength of burglary resistance by applying static and dynamic loads, which may precede testing using a tool or other possible burglary equipment.

Table 4. Main characteristics of the strength category in terms of burglary resistance

The GOST R 51072 standard sets requirements for locking devices of security doors (classes A or B), which must ensure secrecy according to the data in Table 5. Locking devices are tested as part of doors for resistance only to destructive effects of tools specified by the standard. During testing, one attempt is made to achieve full access by acting on the locking mechanism. Breaking methods are determined depending on the design features of the locking mechanism and the sample as a whole. During testing, non-destructive effects on locking devices such as key or master key selection, code selection and other similar manipulations are prohibited.

Table 5. Lock Secrecy Classes

In 1998, GOST 5089-97 «Locks and Latches for Doors. Technical Conditions» was approved. The approval was preceded by extensive work by the Research Center «Security» of the Main Directorate of the Ministry of Internal Affairs of Russia and the Central Design Bureau of the Main Sanitary and Industrial Industry of Russia to establish requirements for the resistance of locks to burglary and the introduction of lock resistance classes.

The work began in 1991 with the study of foreign experience and research of domestic mass-produced locks. More than 40 types of locks from various manufacturers were tested according to a specially developed program. Locks were tested to ensure that they met the requirements for reliability, strength, ergonomics and operational forces, and were in compliance with the requirements of GOST 5089-90 «Locks and latches for wooden doors. Types and main dimensions». Locks that passed this volume of testing were tested for resistance to the following types of burglary:

• sawing the bolt:

• drilling out the elements of the secrecy mechanism:

• applying torque to the secrecy mechanism:

• applying dynamic loads to the bolt:

• destroying the head of the lock with an impact load in order to provide access to the secrecy mechanism.

At the same time, tests of locks for resistance to non-destructive methods of opening were conducted. The results of the work were used in preparing the version of GOST 5089-97. The standard applies to locks and latches for doors (in residential and public buildings) and establishes their classes, main parameters, and dimensions. A separate subsection of the technical requirements introduces requirements for resistance and opening (burglary). Classes, class characteristics, requirements for strength and resistance of locks to destructive and non-destructive methods of opening are given in Table 6.

Table 6. Lock classes by burglary resistance

Locks of classes 2-4 are subject to mandatory certification, during which compliance with the parameters of Table 6 is established, as well as the following burglary resistance requirements:

•the secrecy mechanism of locks of classes 2-4 must have protection against drilling and opening with master keys:

• the escutcheons of mortise locks of classes 2-4 must be secured with screws.

Locks of classes 3 and 4 must also have a bolt projection of at least 25 mm and protection against bolt sawing. The posts of the shank of lever locks of classes 3 and 4 must have protective elements against drilling. Certain requirements affecting the resistance of locks to opening (burglary) are included in the design requirements, and compliance with these requirements is also checked during testing. The standard also establishes the required number of lock secrets depending on the number of secret elements and the mean time between failures in cycles for lock types. The standard specifically establishes that when putting into production and when certifying newly developed locks, it is necessary to conduct tests for reliability, strength, and operational forces in funded test centers, and tests for indicators of the resistance of locks to opening (burglary) according to the methods of testing laboratories of the Ministry of Internal Affairs.