Author Topic: Inner inner room  (Read 786 times)

Offline Karissa

  • New Member
  • Newbie
  • *
  • Posts: 41
Inner inner room
« on: March 27, 2023, 12:30:42 PM »
Are inner inner rooms an absolute no-no or can you risk assess it out?

Offline Messy

  • Sr. Member
  • ****
  • Posts: 343
Re: Inner inner room
« Reply #1 on: March 27, 2023, 04:34:07 PM »
I have risk assessed them out in the past, but only in truly exceptional and low risk situations

Can you give a bit more info re the circumstances?

Offline Karissa

  • New Member
  • Newbie
  • *
  • Posts: 41
Re: Inner inner room
« Reply #2 on: March 28, 2023, 07:27:43 AM »
Thanks Messy

A single small room (7.5m x 5.5m) is being turned into a clean room which consists of a gowning room entrance, leading into a workspace, with another workspace off that workspace. It is labs type work, there is full AFD in all rooms, around 2-4 people in total, the main issue might be travel distance due to the layout as you could be right next to the door into the corridor but you've got to go all the way round. I can make the travel distance over 18m if I measure a very long way round. Travel distance unlikely to be less than 12m. I've attached a plan layout to help explain

Edit plan not to scale  :D

Offline Messy

  • Sr. Member
  • ****
  • Posts: 343
Re: Inner inner room
« Reply #3 on: March 28, 2023, 09:12:49 AM »
This looks like a set up in a lab I was involved with where multiple lobbies were installed to control a positive pressure differential between the labs and the rest of the building. It was further complicated by a computer controlled door entry system that in 'working' mode, controlled the door locking mechanisms to ensure the doors wouldn't open until pressures were equalised. (like a canal lock gate).

The local fire safety enforcement team were a bit grumpy as they saw the plans as an inner, inner, inner room and were having little panic attacks which also resulted in a bit of professional deafness - in that they were not interested in the use of the space, any mitigations in place or any other matter. It was a triple inner room and its not happening. They also didnt like that we wouldn't let them in to view the lab for technical reasons

The strategy I compiled looked at the rationale as to why in the fire safety world inner/inner rooms are seen as high risk - ie a fire developing unseen to those in the deepest room. Then I introduced the fact we had AFD in each room and aspirating SD in the false ceiling and raised floor voids, plus overrides on each door-set that would allow escape regardless of the ambient air pressures.

The testing of the AFD was more onerous than BS 5839, we promised (but TBH rarely achieved!) 4 x fire drills per annum and introduced a policy that where detection fails in a lab, it will not be occupied  There were three identical labs and the AFD was arranged so each space was on a separate system so a fault in one, wouldn't take all 3 labs out of use. In the very unlikely circumstances that all 3 AFD systems failed, extra staff would be employed as fire watchers for the duration of the use of the one single lab.

So it was my view the MoE was protected adequately my both infrastructure and management systems - and the enforcement team reluctantly agreed

It seems like the biggest difference between my scenario and yours is that we had numerous sterile lobbies with no storage and only lighting, & door entry equipment as ignition sources. So when justifying you gowning area, you may have to show mitigation such as reducing the amount of PPE stored there or the time it is stored there etc.

Good luck

Offline Dinnertime Dave

  • Hero Member
  • *****
  • Posts: 819
Re: Inner inner room
« Reply #4 on: March 29, 2023, 11:08:12 PM »
There are plenty of inner inner rooms out there. Radio studios, laboratories and cash offices to name just three.