Incident Report

Subject:                                  Suction Hose (Failure) - Are you fully appreciative of it's limitations.  

Date of Email reporting Incident:   Thu 26/06/2003 07:06

Report Detail:

Please note an incident which happened at our facility, it may serve as a reminder to others that care must be taken - and use must be made of the appropriate equipment and work within it's design limits.  The US specification suction hose used is unusual in that it is 8" and larger (but lighter) than that normally found within the UK fire industry.  The following is an initial note by the officer in charge followed by my response:

Following the water trials which were requested by Red 1 India to be carried out on the Low Pressure Sump Hydrant situated at the rear of the Fire Station. Please find following the events which lead up to the Failure of the 8" hard Suction Hose.

At approx 12:30hrs we commenced the water trials at the rear of the Fire Station. Site Protection Officer (SPO)  XXXX  and SPO XXXX  were operating the Pump within the E-One and I was on the Hydrant. Duty Station Commander & SPO XXXX were operating the Six Gun Monitor which was positioned across the road on waste ground opposite AP&L HQ.

All High Volume hose had been ran out using the High Volume Hose Trailer and all 5 " Hose coupled up to the Deliveries on the E-One. The 8" Hard Suction Hose from the E-One was connected from the Sump manifold to the E-One 8" intakes.

Once all Hose had been connected we received the request for 'Water' from Red 1 Bravo. SPO XXXX then firstly opened 1 x 70mm delivery and I commenced to open the 2 x Sump Valves to provide water to the Appliance.

Whilst opening the Sump valve I could see the water beginning to back fill the 2 x 8" Hard Suction Hose. I immediately started to turn the valves off but was unable to shut them off completely before the Hard Suction Hose began to pressurise and part from its couplings. It was also at this time that 1 x 8" Hard Suction Hose was noticed to have a split in and due to the pressure within the Hose this was made more evident. We are unsure as to whether this Burst length had been caused by ourselves or if in fact the length had been damaged previously.

I contacted red 1 Bravo via to inform him of the fault with the equipment and he immediately came to our location to inspect the damage. After consultation he contacted Red 1 India and informed him of the faults that had occurred during the Water Trials.

At approx 15:02hrs Red 1 India attended and at approx 15:10hrs Red 1 Oscar attended the scene.

IMPORTANT

Very interesting shots of the Hi Vol hose.

All attempts must be made to ensure suction hose is not used under pressure. Deliveries can and should be opened when a positive suction head is experienced as with the large diameter manifolds at the back of the fire station. The hose supplied in the UK in general can withstand internal pressures as well as vacuum pressures. I insert for you attention a diagram of the (heavy duty) suction hose in general use in the UK. You will see that this is of a far more complex design, but considerably heavier.

 

The construction of the hose supplied with the Liquidator is NOT designed for internal pressures - and one should not assume that it is. Always check with the supplier/manufacturer if in doubt about specifications and performance criteria for any pressure sensitive equipment.

Here is a note from NFPA 1962 Standard for the Care, Use, and Service Testing of Fire Hose Including Couplings and Nozzles

Suction hose manufactured in accordance with the 1992 edition of NFPA 1961, Standard on Fire Hose, will be marked FOR VACUUM USE ONLY if it is designed for use under vacuum only. If the suction hose is designed for use under positive pressure, it will be marked SERVICE TEST TO (the service test pressure) AND 22 IN. HG. VACUUM PER NFPA 1962.

PVC suction hose is not designed for use under positive pressure. If unmarked suction hose is to be used under positive pressure, the user should check with the manufacturer to be sure the hose is designed for such applications.

I guess the hose has suffered from age (exposure to UV degradation and abrasion) and this will have had a bearing on the failure and its performance, however, please be aware that US suction hose is for suction from an open  water supply ONLY.