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SST (Other exams) practice questions

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Question 1Safety and Security Technology Fundamentals

In a safety instrumented system, what does the term SIL primarily quantify?

  1. The risk reduction a safety function is credited with achieving Correct answer.
  2. The number of field devices installed per safety loop
  3. The response time of the logic solver under fault conditions
  4. The redundancy level of the plant's process control network

Explanation

Safety Integrity Level expresses the degree of risk reduction a safety instrumented function is designed to provide, tied to target failure measures such as PFDavg for low-demand operation. It is a reliability/performance target for the function, not a hardware count or network property.

Question 2Safety and Security Technology Fundamentals

A safety function operates in low-demand mode. Which measure is the appropriate basis for assigning its SIL?

  1. Average probability of failure on demand Correct answer.
  2. Mean time to repair after a detected fault
  3. Frequency of spurious trips per year
  4. Proof-test interval in calendar months

Explanation

For low-demand safety functions, integrity is expressed as PFDavg, the average probability that the function fails to act when a demand occurs. Spurious trip rate, proof-test interval, and repair time are design parameters that influence PFDavg but are not the integrity measure itself.

Question 3Safety and Security Technology Fundamentals

What is the primary purpose of a proof test in a safety instrumented function?

  1. To validate that the safety function meets its spurious trip target
  2. To verify that the operator interface displays the correct process units
  3. To reveal dangerous undetected failures so the function's integrity is restored Correct answer.
  4. To confirm the control valve sizing matches the process flow rate

Explanation

A proof test exercises the safety function to expose dangerous failures that diagnostics cannot detect, returning the function to its assumed integrity level. It is distinct from calibration, sizing checks, and nuisance-trip validation.

Question 4Safety and Security Technology Fundamentals

A transmitter has a detected failure rate and an undetected failure rate. Which portion is reduced by automatic diagnostics in the logic solver?

  1. The common cause factor, because diagnostics break shared-cause dependencies
  2. The dangerous undetected failure contribution, because diagnostics eliminate all hidden faults
  3. The safe failure fraction, because diagnostics remove safe failures from the calculation
  4. The dangerous detected failure contribution, because diagnostics convert hidden faults into alarms Correct answer.

Explanation

Diagnostics can only detect failures they are designed to sense, moving them from undetected to detected so maintenance can act. They cannot eliminate undetected failures entirely, cannot change the intrinsic safe failure fraction, and cannot remove common cause vulnerability.

Question 5Safety and Security Technology Fundamentals

Which term describes the fraction of dangerous failures that diagnostics are able to detect?

  1. Hardware fault tolerance
  2. Safe failure fraction
  3. Proof-test coverage
  4. Diagnostic coverage Correct answer.

Explanation

Diagnostic coverage is the ratio of detected dangerous failure rate to total dangerous failure rate. Safe failure fraction is a different ratio involving safe and detected failures, hardware fault tolerance counts tolerated faults, and proof-test coverage is not a standard integrity parameter.

Question 6Safety and Security Technology Fundamentals

A subsystem is architecturally tolerant of one dangerous fault and can still perform its safety function. What is its hardware fault tolerance?

  1. 2
  2. 3
  3. 0
  4. 1 Correct answer.

Explanation

Hardware fault tolerance is the number of dangerous faults a subsystem can tolerate and still execute its safety function. Tolerating exactly one fault corresponds to HFT of 1, while 0 means a single fault defeats the function.

Question 7Safety and Security Technology Fundamentals

Why does a redundant 1oo2 sensor architecture not reduce risk by the full factor implied by independent failures alone?

  1. Common cause failures can defeat both channels simultaneously Correct answer.
  2. Redundant sensors always share the same proof-test interval
  3. The logic solver cannot read two input channels at once
  4. Voting degradation converts dangerous failures into safe failures

Explanation

Redundancy gains are limited by common cause failures such as shared impulse lines, environment, or maintenance errors that can disable multiple channels at once. Beta factor modeling accounts for this, so the achieved risk reduction is lower than pure independence would suggest.

Question 8Safety and Security Technology Fundamentals

In a 2oo3 voting arrangement, what happens to the safety function when one channel is detected as failed and is bypassed?

  1. The group loses its safety function entirely until repair
  2. The group degrades to 1oo2 behavior, so any one remaining channel can trip Correct answer.
  3. The group requires all three channels to agree before tripping
  4. The group converts to a 2oo2 arrangement requiring both channels to trip

Explanation

With one channel removed, two healthy channels remain and the vote effectively becomes 1oo2, where either remaining channel can initiate the trip. This preserves safety but increases spurious trip likelihood.

Question 9Safety and Security Technology Fundamentals

What distinguishes a safety instrumented system from a basic process control system?

  1. It regulates the process continuously to maintain setpoints during normal operation
  2. It manages alarm annunciation on the operator console during normal operation
  3. It brings the process to a safe state when demand occurs, independent of normal control Correct answer.
  4. It records process history for production reporting and trend analysis

Explanation

A safety instrumented system is designed to take the process to a safe state on demand and is kept functionally separate from normal regulatory control. Basic control maintains setpoints, while historian and alarm functions support operations but are not the safety layer.

Question 10Safety and Security Technology Fundamentals

Which document defines the required safety instrumented functions, their target SILs, and the process safe state?

  1. The preventive maintenance schedule
  2. The safety requirements specification Correct answer.
  3. The loop wiring diagram
  4. The instrument index

Explanation

The safety requirements specification captures the functional and integrity requirements for each safety instrumented function, including target SIL and safe state. Wiring diagrams, instrument indexes, and maintenance schedules support implementation but do not define the requirements.

Question 11Safety and Security Technology Fundamentals

A pressure protection loop must respond before the vessel exceeds its design pressure. Which parameter establishes the maximum time allowed for sensor, logic, and final element combined?

  1. The process safety time Correct answer.
  2. The scan time of the controller
  3. The proof-test interval
  4. The mean time between failures

Explanation

Process safety time is the window within which the safety function must act to prevent the hazardous event, and the total loop response must fit inside it. Proof-test interval, controller scan time, and MTBF describe other performance aspects.

Question 12Safety and Security Technology Fundamentals

Which practice best supports functional separation between the basic process control system and the safety instrumented system?

  1. Using independent sensors and separate logic hardware for the safety function Correct answer.
  2. Sharing a single transmitter between control and safety to reduce cost
  3. Configuring the safety logic in the same controller as regulatory control
  4. Routing both systems through the same network switch for simplicity

Explanation

Independence of sensors and logic hardware reduces common cause and common mode failures between control and safety layers. Sharing transmitters, network equipment, or controllers undermines that independence and weakens the safety case.

Question 13Safety and Security Technology Fundamentals

What does a beta factor represent in common cause failure modeling?

  1. The fraction of proof tests that are performed incorrectly
  2. The fraction of failures that affect multiple redundant channels at the same time Correct answer.
  3. The ratio of safe failures to dangerous failures in a device
  4. The proportion of spurious trips caused by instrument drift

Explanation

The beta factor estimates the share of a channel's failure rate that is common to redundant channels, capturing shared causes like environment or maintenance. It is used to adjust the reliability of voted architectures away from ideal independence.

Question 14Safety and Security Technology Fundamentals

Which failure mode is most directly addressed by increasing the frequency of proof testing?

  1. Systematic design errors in the logic
  2. Dangerous undetected failures Correct answer.
  3. Safe detected failures
  4. Spurious trips caused by noise

Explanation

More frequent proof testing shortens the average time a dangerous undetected failure remains hidden, lowering PFDavg. It does not remove safe detected failures, noise-induced trips, or systematic design errors, which require design and diagnostic measures.

Question 15Safety and Security Technology Fundamentals

A final element such as a shutdown valve is often the weakest part of a safety loop. Which characteristic most explains this?

  1. It has fewer diagnostic options and is subject to mechanical wear and partial stroke limitations Correct answer.
  2. It operates at higher electrical voltage than the sensor
  3. It is always located downstream of the logic solver
  4. It is excluded from the safety requirements specification

Explanation

Final elements typically have limited diagnostic coverage, mechanical degradation, and infrequent full-stroke testing, which raises their undetected failure contribution. Their position, voltage, and specification coverage are not the root cause of weakness.

Question 16Safety and Security Technology Fundamentals

What is the purpose of partial stroke testing on an emergency shutdown valve?

  1. To measure the valve's flow coefficient at operating conditions
  2. To fully verify the valve closes within its required stroke time
  3. To calibrate the valve positioner to the process setpoint
  4. To detect some stuck-valve failures without fully closing the valve during operation Correct answer.

Explanation

Partial stroke testing moves the valve through a limited travel to reveal certain failure modes, improving diagnostic coverage without disrupting the process. It does not replace a full stroke test, calibrate the positioner, or measure flow capacity.

Question 17Safety and Security Technology Fundamentals

Which layer of protection is credited in a layer of protection analysis as independent of the safety instrumented function?

  1. An additional proof test of the same safety function
  2. A redundant channel within the same safety function
  3. A second sensor voting in the same safety loop
  4. A relief valve sized for the credible overpressure scenario Correct answer.

Explanation

An independent protection layer must be separate from the initiating cause and other layers, so a mechanical relief device can be credited alongside a safety function. Redundant channels and extra proof tests strengthen the same function rather than adding an independent layer.

Question 18Safety and Security Technology Fundamentals

In layer of protection analysis, what does an independent protection layer need to satisfy?

  1. Low cost, high speed, low power, and small footprint
  2. Specificity, independence, dependability, and auditability Correct answer.
  3. Redundancy, redundancy, redundancy, and redundancy
  4. Manual operation, operator training, alarm response, and reporting

Explanation

An independent protection layer must be specific to the scenario, independent of the initiating cause and other layers, dependable in achieving its function, and auditable to confirm ongoing performance. Cost, size, and generic operator actions do not qualify a layer.

Question 19Safety and Security Technology Fundamentals

Which activity belongs to the functional safety management lifecycle rather than to routine plant operation?

  1. Verifying that each safety function meets its specified SIL before commissioning Correct answer.
  2. Replacing a fouled filter element during scheduled maintenance
  3. Adjusting a controller tuning parameter to reduce oscillation
  4. Recording daily production totals for shift reporting

Explanation

SIL verification is a lifecycle activity confirming the designed function achieves its target integrity before it is placed in service. Tuning, production reporting, and routine maintenance are operational tasks outside the functional safety assessment.

Question 20Safety and Security Technology Fundamentals

A safety function has a PFDavg of 0.005. Which SIL does this correspond to under the common low-demand scale?

  1. SIL 2 Correct answer.
  2. SIL 3
  3. SIL 1
  4. SIL 4

Explanation

On the low-demand scale, SIL 2 spans PFDavg from 0.001 to 0.01, so 0.005 falls within SIL 2. SIL 1 covers 0.01 to 0.1, SIL 3 covers 0.0001 to 0.001, and SIL 4 covers 0.00001 to 0.0001.

Question 21Safety and Security Technology Fundamentals

What is the main benefit of a diverse redundant architecture using different technologies for the same safety function?

  1. It guarantees the function achieves SIL 4
  2. It removes the need for a safety requirements specification
  3. It reduces susceptibility to common cause and common mode failures Correct answer.
  4. It eliminates the need for any proof testing

Explanation

Diversity in technology or design reduces the chance that a single shared cause disables both channels, lowering common cause vulnerability. It does not eliminate proof testing, guarantee a specific SIL, or replace the requirements specification.

Question 22Safety and Security Technology Fundamentals

Which metric best indicates the fraction of failures that are safe or detected relative to all failures in a subsystem?

  1. Probability of failure on demand
  2. Spurious trip rate
  3. Mean downtime
  4. Safe failure fraction Correct answer.

Explanation

Safe failure fraction is the ratio of safe failures plus detected dangerous failures to total failures, used in architecture assessments. PFD is an integrity measure, mean downtime relates to availability, and spurious trip rate describes nuisance trips.

Question 23Safety and Security Technology Fundamentals

What does a safety instrumented function's specified safe state describe?

  1. The process condition the function drives to in order to avoid or limit the hazard Correct answer.
  2. The normal operating setpoint maintained by the control system
  3. The condition of the field wiring during commissioning
  4. The state of the logic solver after a firmware update

Explanation

The safe state is the defined process condition the safety function brings about to prevent or mitigate harm. It is not the normal control setpoint, a software state, or a wiring condition.

Question 24Safety and Security Technology Fundamentals

A safety function must operate in high-demand or continuous mode. Which measure is then used to express its integrity?

  1. Average frequency of dangerous failures per hour Correct answer.
  2. Proof-test interval in months
  3. Mean time to spurious trip
  4. Average probability of failure on demand

Explanation

For high-demand and continuous mode functions, integrity is expressed as the average frequency of dangerous failures per hour rather than PFDavg. Proof-test interval and spurious trip timing are separate parameters.

Question 25Safety and Security Technology Fundamentals

Why is a systematic capability considered separately from random hardware reliability in safety instrumented systems?

  1. Systematic failures are always detected by automatic diagnostics
  2. Systematic failures are excluded from the safety lifecycle
  3. Systematic failures only occur during proof testing
  4. Systematic failures arise from design and specification errors that reliability data cannot predict Correct answer.

Explanation

Systematic failures stem from design, specification, and software errors, so they are controlled through rigorous processes and assessed as systematic capability rather than predicted by failure-rate data. Diagnostics cannot reliably detect them, and the lifecycle explicitly addresses them.

Question 26Safety and Security Technology Fundamentals

Which term describes the ability of a safety instrumented function to perform its specified function under stated conditions for a stated period of time?

  1. Availability
  2. Maintainability
  3. Survivability
  4. Reliability Correct answer.

Explanation

Reliability is defined as the probability that an item performs its required function under stated conditions for a stated period. Availability instead concerns the fraction of time the function is able to operate, regardless of whether it is actually needed. Maintainability describes how easily the item can be restored, not the probability of performing the function.

Question 27Safety and Security Technology Fundamentals

A safety instrumented system is credited with reducing the frequency of a hazardous event. Which characteristic must that system have for the credit to be valid in a layer of protection analysis?

  1. It must share final elements with the basic process control system
  2. It must be operated by the same logic solver as the control system
  3. It must be tested only during major turnarounds
  4. It must be independent of the initiating cause and the other protection layers Correct answer.

Explanation

An independent protection layer must be independent of the initiating cause and of other credited layers, so that a single failure or common cause cannot defeat both the cause and the protection. It must also be specific, dependable, and auditable. Sharing final elements or logic solvers with the control system destroys that independence.

Question 28Safety and Security Technology Fundamentals

During a factory acceptance test, a safety controller is subjected to electromagnetic disturbance testing. Which category of requirement does this testing primarily verify?

  1. Random hardware failure rate
  2. Systematic capability of the application software
  3. Immunity to environmental influences Correct answer.
  4. Proof test coverage of the sensor

Explanation

Electromagnetic disturbance testing checks immunity, meaning the equipment continues to function correctly when exposed to conducted or radiated interference. Immunity is part of the environmental robustness requirements placed on safety hardware. It does not measure failure rates, application software capability, or sensor test coverage.

Question 29Safety and Security Technology Fundamentals

Which arrangement describes a safety function in which two independent channels must both call for action before the output is de-energized?

  1. 1oo1
  2. 1oo2 Correct answer.
  3. 2oo2
  4. 2oo3

Explanation

In a 1oo2 architecture, either channel alone can trip the output, meaning it takes one out of two to act; this gives high safety availability but lower spurious trip resistance. The naming convention states how many channels must agree to trip. A 2oo2 arrangement requires both channels to agree before tripping.

Question 30Safety and Security Technology Fundamentals

A safety instrumented function must place a reactor in a safe state within 30 seconds of a high-temperature trip. Which specification element does the 30 seconds define?

  1. Safety response time Correct answer.
  2. Mean time to repair
  3. Mission time
  4. Proof test interval

Explanation

The safety response time is the time allowed for the entire safety function, from sensor detection through logic processing to the final element reaching the safe state. It is a key element of the safety requirements specification alongside the trip point and safe state. Proof test interval, repair time, and mission time describe different lifecycle parameters.

Question 31Safety and Security Technology Fundamentals

A shutdown valve on a safety instrumented function is found to have a dangerous undetected failure rate that dominates the loop. Which action most directly reduces the loop's average probability of failure on demand?

  1. Shortening the proof test interval Correct answer.
  2. Increasing the valve stroke time
  3. Adding a positioner to the actuator
  4. Increasing the trip setpoint margin

Explanation

For a low-demand function, average probability of failure on demand is approximately proportional to the dangerous undetected failure rate multiplied by half the proof test interval. Shortening that interval therefore reduces the average PFD directly. Changes to stroke time, positioner hardware, or setpoint margin do not alter the hidden failure exposure in the same direct way.

Question 32Safety and Security Technology Fundamentals

Which failure classification applies to a detected failure that prevents the safety function from acting when demanded?

  1. Safe detected
  2. Dangerous undetected
  3. Dangerous detected Correct answer.
  4. Safe undetected

Explanation

A dangerous detected failure is one that would prevent the safety function from performing as required and that is revealed by diagnostics or proof testing. Detection matters because it allows the system to respond, for example by degrading to a safer state or raising an alarm. Dangerous undetected failures are the ones that remain hidden until a demand or proof test.

Question 33Safety and Security Technology Fundamentals

An engineer must choose between a single-channel trip amplifier and a redundant configuration for a high-demand safety function. Which consideration most strongly favors the redundant configuration?

  1. Redundancy reduces the probability of dangerous failure on demand from random causes Correct answer.
  2. Redundancy guarantees the safe state is reached faster
  3. Redundancy removes the need for proof testing
  4. Redundancy eliminates systematic design faults in the logic

Explanation

Redundancy improves the random hardware reliability of the function by providing alternative paths, lowering the probability of dangerous failure. It does not address systematic faults, which arise from design and specification errors and are handled through process measures. It also does not remove the need for testing or guarantee faster response.

Question 34Safety and Security Technology Fundamentals

Which document records the assumptions, justification, and verification evidence for each safety instrumented function throughout its lifecycle?

  1. Operator training manual
  2. Loop wiring schedule
  3. Piping and instrumentation diagram
  4. Safety requirements specification Correct answer.

Explanation

The safety requirements specification captures the required functions, integrity targets, response times, safe states, and the assumptions and evidence supporting them. It is the reference against which design, verification, and later modification are checked. Piping diagrams, wiring schedules, and training manuals support implementation but do not hold the safety requirements and their justification.

Question 35Safety and Security Technology Fundamentals

A risk graph assessment places a process hazard in a category requiring SIL 2. The design team proposes a SIL 2 certified logic solver but non-certified final elements. What is the most defensible conclusion?

  1. Each element must be evaluated so the combined loop meets the SIL 2 target Correct answer.
  2. The SIL target applies only to the sensor subsystem
  3. Certification of any single element is sufficient for the whole loop
  4. The loop automatically achieves SIL 2 because the logic solver is certified

Explanation

The SIL target applies to the safety instrumented function as a whole, so the sensor, logic solver, and final elements must be evaluated together to show the combined integrity meets the target. A certified logic solver alone does not guarantee the loop achieves SIL 2. Element-level claims must be combined with architecture constraints and systematic capability considerations.

Question 36Safety and Security Technology Fundamentals

Which measure expresses the fraction of dangerous failures that are revealed by automatic diagnostics?

  1. Hardware fault tolerance
  2. Diagnostic coverage Correct answer.
  3. Proof test coverage
  4. Safe failure fraction

Explanation

Diagnostic coverage is the ratio of dangerous failures detected by automatic diagnostics to all dangerous failures in the subsystem. It is used when calculating the detected and undetected portions of the failure rate. Safe failure fraction and hardware fault tolerance are architectural parameters, while proof test coverage relates to manual testing.

Question 37Safety and Security Technology Fundamentals

A safety instrumented function is credited with a risk reduction factor of 500. Which low-demand SIL does this correspond to?

  1. SIL 4
  2. SIL 3 Correct answer.
  3. SIL 2
  4. SIL 1

Explanation

On the common low-demand scale, SIL 3 covers a risk reduction factor from 1000 down to 100, and SIL 2 covers 100 down to 10. A risk reduction factor of 500 falls between 100 and 1000, so it lies in the SIL 2 band, not SIL 3. Care is needed because the bands are defined by ranges, and 500 is below the SIL 3 threshold of 1000.

Question 38Safety and Security Technology Fundamentals

Why does a higher hardware fault tolerance generally permit a lower safe failure fraction for the same SIL?

  1. Fault tolerance removes systematic faults from the design
  2. Redundant channels allow the subsystem to tolerate a dangerous fault without losing the safety function Correct answer.
  3. Higher fault tolerance increases the proof test interval automatically
  4. Fault tolerance lowers the demand rate on the safety function

Explanation

Hardware fault tolerance means the subsystem can continue to perform its safety function in the presence of one or more dangerous faults. Because a single fault does not immediately defeat the function, the architecture can qualify for a given SIL with a lower proportion of safe or detected failures. Fault tolerance does not address systematic faults or change the demand rate.

Question 39Safety and Security Technology Fundamentals

Which activity is performed during the safety instrumented system design phase rather than during operation?

  1. Allocating the safety requirements to sensors, logic solver, and final elements Correct answer.
  2. Scheduling periodic proof tests
  3. Reviewing bypass requests from maintenance
  4. Investigating a demand that resulted in a trip

Explanation

Requirement allocation assigns each part of the safety function to specific hardware and software elements, which is a design-phase activity. Proof test scheduling, demand investigation, and bypass review all occur during operation and maintenance. Allocation provides the basis for later verification that each element can meet its assigned integrity.

Question 40Safety and Security Technology Fundamentals

A safety instrumented function uses a sensor with a dangerous undetected failure rate of 2E-6 per hour and a proof test interval of 8760 hours. Assuming a simplified 1oo1 model with negligible repair time, what is the approximate average probability of failure on demand?

  1. 0.0000175
  2. 0.000002
  3. 0.0175
  4. 0.0088 Correct answer.

Explanation

For a 1oo1 low-demand element, average PFD is approximately the dangerous undetected failure rate multiplied by half the proof test interval. That gives 2E-6 times 4380, which equals about 0.0088. The factor of one half reflects the uniform distribution of failure times within the test interval.

Question 41Physical Security Systems and Access Control

In a card-based access control system, what does the reader primarily do when a credential is presented?

  1. It stores the full access authorization database and grants access locally
  2. It physically unlocks the door by supplying power directly to the strike
  3. It captures the credential data and transmits it to the controller for a decision Correct answer.
  4. It logs entry events permanently to a local hard drive for audit purposes

Explanation

The reader is an input device: it reads the credential and passes the identifier to the access control panel, which makes the grant or deny decision. Locking hardware is driven by the controller, not the reader. Readers generally hold no authorization database.

Question 42Physical Security Systems and Access Control

Which locking device holds the door secure when power is removed, making it the preferred choice for life-safety egress paths?

  1. Fail-secure electric strike
  2. Fail-safe electromagnetic lock Correct answer.
  3. Fail-locked motorized deadbolt
  4. Fail-secure solenoid bolt

Explanation

Fail-safe hardware releases when power is lost, allowing free egress during fire or power failure. Fail-secure devices remain locked without power and are used where security outweighs free egress. Life-safety codes generally require fail-safe release on egress doors.

Question 43Physical Security Systems and Access Control

A proximity reader using 125 kHz technology is typically associated with which credential characteristic?

  1. Smart-card cryptographic challenge-response
  2. Low-frequency operation with limited data security Correct answer.
  3. Encrypted mutual authentication with the reader
  4. Long read range exceeding one meter

Explanation

125 kHz proximity is a low-frequency technology with short read range and generally no cryptographic protection, making cloning relatively easy. Encrypted mutual authentication and challenge-response are features of higher-frequency smart cards such as 13.56 MHz systems.

Question 44Physical Security Systems and Access Control

What is the primary purpose of a request-to-exit (REX) device in an access-controlled opening?

  1. To log the identity of the person leaving the secured area
  2. To allow free egress without triggering an alarm or requiring a credential Correct answer.
  3. To hold the door open for a programmed delay period
  4. To arm the intrusion detection system when the door closes

Explanation

A REX device such as a passive infrared sensor or push button signals the controller that a person is exiting, so the door releases without a credential and without generating a forced-door alarm. It does not identify the person leaving. Door-hold timing is a separate controller function.

Question 45Physical Security Systems and Access Control

Which component converts a controller's low-voltage output into the higher current needed to drive a magnetic lock?

  1. A door position switch
  2. A network video recorder
  3. A power supply with a lock relay or board Correct answer.
  4. A credential reader interface

Explanation

A dedicated power supply, often with a lock control board or relay, provides the current and switching needed for locking hardware. Readers, door position switches, and recorders do not supply lock power. Correct power sizing prevents lock dropout and controller damage.

Question 46Physical Security Systems and Access Control

A door position switch (DPS) is installed on a controlled door. What condition does the controller detect when the switch reports open while no valid access was granted?

  1. A forced door Correct answer.
  2. A held-open door
  3. A duress alarm
  4. A reader tamper

Explanation

When the door opens without a prior valid grant, the controller reports a forced-door alarm. A held-open condition occurs when the door remains open past its allowed time after a valid grant. Duress and tamper conditions come from other inputs.

Question 47Physical Security Systems and Access Control

Which standard commonly governs the minimum requirements for access control systems used in classified U.S. government facilities?

  1. FIPS 201 Correct answer.
  2. NFPA 72
  3. ASHRAE 90.1
  4. UL 294

Explanation

FIPS 201 defines the Personal Identity Verification requirements for federal employees and contractors, including credential and access control standards. UL 294 addresses access control unit performance, not government identity requirements. NFPA 72 and ASHRAE 90.1 cover fire alarm and energy standards.

Question 48Physical Security Systems and Access Control

What does an interlock (mantrap) configuration accomplish at a secure entrance?

  1. It provides fail-safe release of all doors during a fire alarm
  2. It allows multiple doors to open simultaneously for faster throughput
  3. It prevents a second door from opening until the first door is fully closed and secured Correct answer.
  4. It records video of every person passing through the vestibule

Explanation

An interlock logic ensures only one door in a vestibule can be open at a time, preventing tailgating and controlling the number of people in the space. Simultaneous opening would defeat the purpose. Fire release and video recording are separate functions.

Question 49Physical Security Systems and Access Control

A facility wants to detect tailgating at a single door without requiring a full turnstile. Which technology is best suited for this application?

  1. An overhead people-counting sensor with tailgate detection logic Correct answer.
  2. A door position switch
  3. A glass break detector
  4. A request-to-exit push button

Explanation

Overhead people-counting sensors paired with access control logic can detect when more than one person enters on a single valid grant. A door position switch only reports open or closed. REX buttons and glass break detectors do not count occupants.

Question 50Physical Security Systems and Access Control

An access controller is configured to unlock a door for five seconds after a valid card read. Which term describes this setting?

  1. Rex delay
  2. Strike or unlock time Correct answer.
  3. Shunt time
  4. Anti-passback window

Explanation

Strike or unlock time is the period the lock remains released after a valid grant. Shunt time bypasses an alarm zone for a period. REX delay and anti-passback windows are unrelated timing parameters.