MM Engineering, Unit 14, Seaway Parade, Baglan Energy Park, Port Talbot, SA12 7BR.

Blast Doors

Our blast doors designs have been independently tested in accordance with the procedure under ISO/FDIS 16933 to verify their ability to withstand a blast loading.  When a customer specification is received we have the calculations independently verified to ensure the highest levels or protection and performance.  Below are some examples of the different applications for which we can design blast doors.

Explosion and Fire Containment

The most common function of a blast door and its surrounding walls is blast containment.  In this application, the door will remain fully intact and ensuring the blast is fully contained.  During testing, our doors performed to category I, meaning that the door remained closed post-blast and was still fully operable – important should the area required quick evacuation.

Insulation

The storage of munitions requires a dry, temperature-controlled environment.  We design to meet these requirements by using door set insulation and purpose-specific seals to prevent sweating and cold transfer from the external face of the door to the internal face.  This ensures a stable environment for contents of the building whilst maintaining the required level of blast containment.

Blast Windows

Our blast windows have also been independently tested and achieved ISO 16933: 2007 Hazard Rating A.  We use this design of window to provide maximum containment whilst also providing aesthetic value and clear visibility both internal and external to the structure.

The door blast design methodology is as follows:

Static Design Blast Load

– static seated and unseated pressure defined by the client.

– door leaf designed to take the seated blast pressure and remain in the elastic range.

– door hinges and shoot bolts and their connections designed to take the unseated blast pressure.

Dynamic Design Blast Load

– dynamic peak blast pressure, impulse and duration defined by the client.

– door response criteria defined by the client.  e.g. Class I (elastic) or Classes II, III or IV (plastic).

– door leaf designed for the dynamic blast load using a single degree of freedom (SDOF) numerical analysis such that the response (leaf deformation) is within the client defined limits.

– door hinges, shoot bolts and their connections designed for the rebound forces determined by the SDOF analysis.

Blast Windows and Vision panels for Blast Doors

Where vision panels for blast doors or blast windows are required, they shall be designed using a Single Degree of Freedom analysis or the procedure outlined in ASTM E1300. Where a single degree of freedom method is used this shall include both the response of the glass pre-crack and the response of the pvb laminate post crack in accordance with Blast Effects on Buildings 2nd Edition. Alternative methods may be submitted to TCO for acceptance.

Design of anchorage of the window frame to the structure shall be designed to remain elastic based on twice the dynamic reaction from the frame as a static load.

  • Frame may also be designed so that the window glazing will fail prior to failure of the frame.
  • Anchorage of frame to structure may be designed to develop the capacity of the window frame.
  • Supporting structural elements may be designed by dynamic analysis methods.

Laminated glass design is to ensure adequate anchorage of the laminate (e.g. polyvinyl butyral [pvb]) i.e. the laminate does not pull out from the frame rebates or tear.

Glass shall be fully tempered and meet the requirements as specified in ASTM C 1048.

Glazed vision panels shall be minimum 6mm thick laminated glass and shall maintain the fire integrity of the designated door / wall fire resistance.

Laminated glass, tempered glass, and polycarbonates shall be permitted for the windows. Anti-shatter films or bomb blast net curtains should not be used for new windows.

Just so that you are aware, the following are the different requirements for Category I, II, III and IV blast doors:-

Window glazing is not made of metal and so ductility and support rotation limits are not really applicable.   Thus it is not possible to design a window to the above Category descriptions – e.g. a Category II window does not exist.  Instead, glazing response to blast loading is given a Hazard Rating.  In the UK these are defined in ISO 16933 as follows:-

For door vision glazing I would recommend a minimum hazard rating “C” – “Minimal Hazard” as being suitable

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