CISSP Domain 3 Security Engineering – Part 3 – Perimeter Defenses Cheat Sheet


Heating, ventilation, air conditioning.

Positive Pressure and Drains

Air and water should be expelled from the building. Untreated air should be never be inhaled into the building, and water should drain away from the building. A common HVAC malfunction is condensation of water pooling into the building, often going under raised floors where it may not be detected. Positive drains are designed to avoid this problem. Location of all gas and waterlines , as well as all drains should be formally documented.

Heat and Humidity

Datacenters should operate within humidity levels of 40-55% and temperature range of 68-77F (20-25C).

Static and Corrosion

Low humidity can cause static buildup damaging equipment. Maintaining proper humidity and grounding, using antistatic sprays, wrist wraps and work surfaces helps mitigate this risk. High humidity level can allow water in the air to condense onto equipment leading to corrosion.

Airborne Contaminants

Dust can cause overheating and static building, and clog CPU fans causing component failures. HVAC should operating in closed loops require HEPA filters to filter contaminants

Heat, Flame, and Smoke Detectors

Heat Detectors

Alerts when temperature exceeds a certain baseline.

Smoke Detectors

Can be ionization based or photoelectric based. Both types of alarm Alavert when smoke interrupts radioactivity or light, lowering or blocking the electric charge. Dust can sometimes lead to false alarms.

Flame Detectors

Detect infrared or ultraviolet light emitted in fire. The drawback is it requires line of sight from the flame where as smoke detectors don’t.

Personnel Saftey , Training and Awareness

Physical security training and awareness is critical because of the possible stakes; injury or loss of life. Safety is the primary goal of all physical security controls.

Evacuation Routes

All personnel should be advised of the quickest evacuation routes from their area including guest. All sites should use a meeting point in the event of an emergency, so that people don’t mistakenly reenter the site searching for people.

Evacuation Roles and Procedures

  • Safety Warden – Ensures all personnel safely evacuate the building in the event of an emergency or drill
  • Meeting point leader – Assures all personel are accounted for a the emergency meeting point

All personnel should follow evacuation procedures and posted route. All sites should have mitigating controls lot allow safe egress of all personnel.

Duress Warning Systems

Duress warning systems are designed to provide immediate alerts to personnel in the event of emergencies. It maybe include technologies such as overhead speakers, automated email, pagers or phone calls. National duress safety systems include the United States Federal Communcation Commissions Emergency Alert System.

Travel Safety

Personnel must be safe while working in all phases of the business. Work performed on site, authorized work from home, and business travel. Telecommutes should have proper equipment, including ergonimically safe workstations.

ABCD Fires and Suppression

Classes of Fire and Suppression Agenth

  • Class A – Common combustibles such as wood, paper etc. Use water and soda acid to extinguish
  • Class B – Burning alcohol, oil and other petroleum products such as gasolne. Extinguish with gas or soda acid. Never use water
  • Class C – Electrical fire. Must use nonconductive extinguishing agents such as gas. Not soda acid
  • Class D – Burning metals. Extinguish with dry powder
  • Class K – Kitchen fires such as burning oil or grease. Extinguish using wet chemicals

US Fire classes.

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About the Author

Alfred Tong
Author and owner of this blog. A Networking enthusiast, full time networking and systems Engineer. Generally curious about all things IT.Certifications: GIAC GSEC, CCNP-S, CCNP, CCSP, CCDP, CCNA, RHCE, JNCIA - FWV