Hardened Behavioral Psychiatric Rooms

The Behavioral Psychology Rooms are hardened construction to prevent patients from possibly harming themselves or others. The rooms have to go through a certification process which limits the placement and design for wireless access points (AP).

The construction of the room is hardened in the following ways:

  • Ceiling is drywall plus 20 gauge sheet metal. This prevents the patient from escaping through the ceiling.
  • Walls are a mix of thick drywall sheets and plywood. This prevents the patient from escaping through the walls without concerted effort and time.
  • The bathroom is constructed of drywall plus 20 gauge sheet metal plus another layer of 20 gauge sheet metal and drywall. This prevents the patient from breaking into the bathroom without supervision.
  • The external door is a very thick poly core and laminate door on heavy hinges and lock. This prevents the patient from escaping.
  • The walls of the entire floor do not go up to structure. The walls rise to the ceiling and the space above is open.

HardenedRoom1

There were several possible mounting options for the wireless access points (AP) each with their own design constraints and associated costs. I was unable to test every option due to business, architectural, or legal constraints.

The following mounting options were considered:

  • AP mounted below the ceiling in the hardened room.
  • AP mounted to electrical box using a special wall mounted AP.
  • AP mounted under the room’s concrete floor.
  • AP mounted in recessed hole cut into the sheet metal of the ceiling.
  • AP mounted in the hallways using directional patch antennas pointing to the hardened rooms.
  • AP mounted above the hardened ceiling without special attenuation box.
  • AP mounted above the hardened ceiling with special attenuation box.

 

AP mounted below the ceiling in the hardened room.

AP mounted below the ceiling in the hardened room is the most common type of deployment for most medical grade wireless deployments. Not every room would be installed with an AP depending upon the wireless design criteria. This install method uses the attenuation of the walls to help attenuate the radio frequency signal creating smaller wireless cells. The deployment is not challenging to wiring professionals. Replacement of failed AP(s) are also not challenging to wiring professionals. This method of design was not allowed due to patient safety issues.

Status: Not Approved for Deployment

 

AP mounted to electrical box using a special wall mounted AP.

AP mounted to electrical box using a special wall mounted AP. This deployment is used in hospitality verticals for easy of deployment and highly dense deployments. Not every room would be installed with an AP depending upon the wireless design criteria. This install method uses the attenuation of the walls to help attenuate the radio frequency signal creating smaller wireless cells. The deployment is not challenging to wiring professionals. Replacement of failed AP(s) are also not challenging to wiring professionals. This method of design was not allowed due to patient safety issues.

Status: Not Approved for Deployment

 

AP mounted under the concrete floor.

AP mounted under the room’s concrete floor. This deployment can be used in sporting events for very high dense deployments. The design uses the concretes attention to create very small wireless cells, while also protecting the wireless access point from being tampered with. This installation method is challenging for wiring professionals and requires access to the underside of the concrete. This installation method would also be challenging to replace the AP in the event of a failure. It would satisfy the patient safety requirement, since the AP would not be able to be reached by the patient in the hardened room. This method was not selected due to the cost and difficulty of testing, and installation.

Status: Not Approved for Deployment

 

AP mounted in recessed hole cut into the sheet metal of the ceiling.

AP mounted in recessed hole cut into the sheet metal of the ceiling. The ceiling would have been modified by a small circular cutout, and the antenna of the AP would protrude down into the patient room. The backside of the antenna would be held in place by two metal brackets making removal of the antenna very difficult. The antenna also had a small lip that would also prevent the AP from being pulled into the patient room. The deployment would allow the radio frequency energy to enter the room freely similar to the “AP mounted below the ceiling” method. This method was not approved for deployment due to concerns that the State would not approve the modification to the ceiling structure for the hardened patient rooms. See the below photos with the AP Antenna by AccelTex Solutions (AccelTex Solutions).

Status: Not Approved for Deployment

 

AP mounted in the hallways using directional patch antennas pointing to the hardened rooms.

AP mounted in the hallways using directional patch antennas pointing to the hardened rooms. This deployment placed the AP in the hallway and outside the patient room. This satisfies the patient safety issue, however the directional antennas can be aesthetically unappealing. Test results showed reflected or back lobe RF energy was radiating behind the patch antenna into the main area of the building. This would have increased co-channel interference. The wireless design goal was to limit the cell size and to decrease co-channel interference. The deployment is not challenging to wiring professionals. Replacement of failed AP(s) are also not challenging to wiring professionals. This method of design was not chosen due to the propagation of the RF energy from the hallways behind the AP into the main building area.

Status: Not Approved for Deployment

 

AP mounted above the hardened ceiling without special attenuation box.

AP mounted above the hardened ceiling without special attenuation box. This deployment placed the AP suspended by a special mounting bracket above the ceiling. The radio frequency (RF) would radiate down through the sheet metal and drywall of the ceiling. The challenge is that RF waves would also be reflected by the metal ceiling and cause increased loss of wireless data frames. Since the walls do not rise up to structure the AP(s) would also receive greater co-channel interference from AP(s) on the same radio channel. This deployment would be easy to install and to maintain since the AP is set above the ceiling next to an access panel. The concern of the co-channel interference and the impact to the wireless service necessitated the modification of this design to include a box to surround the AP. This box would simulate the attenuation of walls rising up to structure. See the “AP mounted above the hardened ceiling with special attenuation box deployment method”. This method complies with the requirements for patient safety since the AP is above the ceiling and accessible by a locked access panel.

Status: Not Approved for Deployment.

HardenedRoom3

 

AP mounted above the hardened ceiling with special attenuation box.

AP mounted above the hardened ceiling with special attenuation box. The AP is mounted above the metal ceiling with a special mounting bracket. A box that would simulate walls would be placed over the AP to reduce the effects of reflection and side-lobes on the neighboring AP(s). This method complies with the requirements for patient safety since the AP is above the ceiling and accessible by a locked access panel. The concern was the amount of re-transmissions due to the reflection of the signal from the metal ceiling.

The attenuation box was constructed of 5/8” plywood, and 1/2” gypsum board. The box was constructed 16” high by 16” wide by 16” long. The box proved to be heavy and difficult to place due to constrained space from duct-works and other obstructions. After the tests, the box was modified to be 8” high by 16” wide by 16” long with a hole cut into the top for the cable to be routed through for wired connectivity and power. The new box design was not tested. The assumption is that the box will still attenuated by 3dBm and help reduce side lobe propagation and decrease the impact of reflection to the floors above.

Status: Approved for Deployment.

 

The test results were positive. An AP was mounted in a box and placed above the ceiling at different transmit power settings. The signal strength was measured at multiple points in the room and surrounding rooms and hallways. In addition, a speed test server was installed and traffic generated through the AP in an attempt to record the impact of the metal ceiling when actual traffic is being transmitted and received. An AP was also mounted below the ceiling to gather a baseline and acting as a control.

 

The tools used:

  • MacBook Air 11” with integrated 802.11ac wireless nic
  • Ekahau Site Survey Pro
  • Netscout AirCheck
  • Cisco 3702i
  • Cisco 3702e
  • Cisco 6dBi Patch Antenna
  • Fluke 423d laser distance meter
  • Wireless signal generator on small tripod
  • Linux server with Iperf3

The attenuation box reduced the received signal from the neighboring AP by about 3 to 4dBm. A 3dBm reduction halves the signal strength. The results were consistent with the expectations.

HardenedRoom14

The results of the speed test server were also interesting.

When the AP was placed below the ceiling with a TxP of 9dBm at 300 seconds, the re-transmissions were about 15%.

Screen Shot 2016-06-27 at 2.07.08 PM

When the AP was placed above the ceiling with a TxP of 9dBm at 300 seconds the re-transmissions were 15%.

Screen Shot 2016-06-27 at 1.33.08 PM

When the AP was placed below the ceiling with a TxP of 12dBm at 300 seconds, the re-transmissions were about 11%.

Screen Shot 2016-06-27 at 2.18.43 PM

When the AP was placed above the ceiling with a TxP of 9dBm at 300 seconds the re-transmissions were about 16%.

Screen Shot 2016-06-27 at 12.57.51 PM

 

When the AP was placed below the ceiling and tested with Ekahau, the received signal strength indicator (RSSI) was measured at -41dBm.

HardenedRoom10

When the AP was placed above the ceiling and tested with Ekahau, the RSSI was measured at -54dBm.

HardenedRoom11

Proof of concept testing is invaluable when deploying new designs or special designs with unique constraints. I initially was against the AP(s) above the ceiling. After testing, I have decided that it makes the most sense for this deployment.

In the final design, I elected to place AP(s) above each Hardened Room to achieve primary and secondary coverage goals. During post-validation, if the primary and secondary coverage goals are achieved without AP(s) AP07 and AP15, then they will be transitioned into a Monitor Mode AP or removed altogether.

Unity5thFloorWirelessDesignWithMonitorModeAPCrop

My new office!

Psychroom

Disclaimer: This is not the actual hardened rooms. The rooms are still under construction.

Special thank you owed to Chris Kent who was the principle network engineer for the new facility. Thanks Chris!!! You Rock!


3 thoughts on “Hardened Behavioral Psychiatric Rooms

  1. Quick Note that I should have included. The use of directional antennas in the hallways pointing to the rooms was also not chosen. I had thought this would have been the best design, but I didn’t like the testing results for it. Also it would be displeasing to look at and potentially could be ripped off the ceiling by an agitated patient.

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  2. What would be the possibility of using an AP that could utilize the in wall sheet steel as the antenna? That way, you just have an attachment point to the sheet in one place in the room and the room should be good to go. Just a thought.

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    1. I discounted that option for several reasons. Timeframe, not being familiar with the design and more importantly the certification with the FCC and SAR testing process, and ability to service the antenna in the event of failure. It is an interesting idea and I will be talking with some of my associates that are electrical engineers and RF Antenna Gurus in the future about this. Thanks!!!

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