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Recent content by riskengr

  1. riskengr

    Sealing drawings and liability

    So, to recover the thread from its errant direction - No one is aware of State Boards imposing a cradle to grave liability on PEs for designs they have sealed? Any DE PE here? The cases our engineer is referring to apparently involved the collapse of deck and the inaudibility of a fire alarm...
  2. riskengr

    Sealing drawings and liability

    Ron, I understand the responsibility for design flaws and ommissions. Our employee is indicating that the boards (at least in DE) are pushing for PEs to be responsible for the final product as well as their design. According to him there have been two DE cases (a construction mistake and a...
  3. riskengr

    Sealing drawings and liability

    We are evalyuating our practices in regards to overseeing the work of subcontractors and sealing drawings for which we have taken responsible charge of the design. One of our engineers has quoted several cases in which he believes licensees were disciplined by the board when a design they had...
  4. riskengr

    wind vs building air exchange rate

    The idea was to assume all conditions (temperatures,wind direction, etc...) being the same except for wind speed. Stephen Haines, PE, CFEI Haines Fire & Risk Consulting www.hainesfire-risk.com
  5. riskengr

    wind vs building air exchange rate

    Actually we did a prssure test on the building and know the ACH under test conditions (i.e., wind direction and speed, temperature, etc...). We were just looking for a Rule of Thumb or simplified formula to show the client the approximate change in ACH over different wind speeds so that they...
  6. riskengr

    wind vs building air exchange rate

    I'm looking for a ball park figure on the relationship between wind speed and a building's natural air exchange rate(i.e, no mechanical ventilation). A couple sources seem to indicate it is linear, although less than linear as wind speed increases, while others indicate it varies with wind...
  7. riskengr

    Foam bladder tank operation manual

    Don't be fooled by a salesman. I am not aware of any independent tests that show 1% concentrates as being more effective at fire suppression than their 3% cousins. The solution flow rate required for 1% concentrates is the same as for 3% concetrates. The only true difference that I am aware...
  8. riskengr

    Foam bladder tank operation manual

    I believe Ansul may be listing some of their chambers with their 1% AFF. You may want to theck with their Northeast represenative, Jim Schwander ((215) 297-8391). I'm not sure if WF&HC has listed their 1% Thunderstorm with any fixed equipment, but they may have done some testing with it. You...
  9. riskengr

    Fire Doors with Fire Dampers

    This would not be permitted by most fire codes, as there are limits to the type of harware and modifications that can be made on a rated fire door. Take a look at the IFC or the local fire code. Stephen Haines, P.E. Haines Fire & Risk Consulting www.hainesfire-risk.com
  10. riskengr

    Foam bladder tank operation manual

    Acceptance testing can be a bit difficult with a fixed system that is connected to tank foam chambers. In the past I've been involved with tests where the chambers were installed facing outwards and then rotated and bolted to the tank after the test. Most foam systems don't have any test...
  11. riskengr

    Maximum panel area for explosion deflagration venting

    I don't have it handy right now, but I believe there are size and weight restrictions for vents in NFPA 68. The problem is that the weight and the inertia related to larger panels can slow their movement and thus the relieving affect. This can increase the peak pressure experienced in the...
  12. riskengr

    Why does metal spark?

    The American Pertroleum Institute (API) has completed a lot of research on this topic and has published their findings in their Publ 2214. You may want to lookit over if your not familiar with it. In applying it you will need to consider the differences in the ignition energy requirements...
  13. riskengr

    Fire hose flow rate

    You can get a rough estimate by assuming that the hose will flow its maximum flowrate with no pressure left at the end of the hose. Assuming the hydrant stays at 60-psi and you are using 100 ft of open ended 2" hose (pressure drop across the line of 60 psi) you will max out in the area of 300 -...
  14. riskengr

    Foam bladder tank operation manual

    These are usually available from the manufacturer. Akso, it may not be a bad idea to have a mfr. authorized rep. do the fill on the bladder, as ii is my understanding that this can be tricky on some tanks (i.e., the baldder is easily damaged). Services provided include: Fire Protection...
  15. riskengr

    NFPA 11 seems to let one bypass NFPA 20?

    The primary heading for this section reads, "4.2.2 Water and Foam Concentrate Pumps". As a result, anything within the section (4.2.2.1 & so on) applies to both water and foam pumps. An NFPA 20 controller is not required on a manually operated foam systems because there is no need for the...

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