PPV - having fresh breath confidence
Published: 01 April, 2007
Although the technical knowledge behind PPV techniques wasn’t widely available five years ago, it has certainly spread since then. Today, most fire departments are well-acquainted with the use and potential of PPV for small structural firefighting scenarios, such as those involving house fires and other small buildings.
However, increasing demands are being placed on municipal brigades through sophisticated infrastructure projects, such as new tunnels and highrise buildings, which require specialist skills and equipment.
“For this need SuperVac developed the SVU, a powerful oversized ventilator able to displace a large amount of air,” explains Jan Pieter Maarschalk, exclusive dealer for SuperVac outside the US.
The SVU can be mounted on either a trailer or on a dedicated fire truck. The fan is placed on a rotating head and which enables optimal positioning; this driven by a large 2.1 litre petrol-powered 165 Hp engine.
This PPV fan is especially suitable for tunnels because heat, toxic smoke and asphyxiating vapours build up easily during a tunnel emergency – they can cause serious injury and death to the occupants of the tunnel without adequate ventilation.
Gaining access
The other aspect behind PPV is fire service access. Vision can be obscured and entry almost impossible due to sever smoke and heat build-up in a structure.
When positioned correctly, the SVU will redirect the smoke and heat to safe outlet, allowing the fire service to approach the seat of the blaze and in extinguish it.
Jan Pieter comments: “When setting up a large unit like the SVU, consider wind direction, and downstream safety prior to positioning.
He advises: “Always vent from the attack side. Wind plays a major role in determining how effective PPV technology can be. In general, it will lose its effectiveness in wind speeds over 20kph.
“In higher wind speeds, it is best to use it to your advantage. No wildland firefighting operations are planned from the downwind – and this is also true for structural firefighting in high winds.”
As wind speed increases, it is best to make smaller exit openings or to move air at angles to the wind direction, he says. It is physically impossible to overcome high natural wind speeds with a fan, even one as large as the SVU.
Other uses
The SVU is also used in situations such as highrise incidents and decontamination, points out Jan Pieter.
SFS Storm Firefighting Support, based in the port of Rotterdam, specialises in hiring out and selling firefighting equipment, as well as delivering a rapid intervention firefighting and rescue service in case of an emergency. SFS owns an SVU and this is available for rental to municipal fire services in The Netherlands in case of a major emergency.
In Holland, the majority of fire brigades have a standard PPV fan on their pumping appliances or rescue vehicles. However, these fans are relatively small and can blow about 30,000 or 40,000 m3 an hour.
“The SVU can handle at least 1million m3 of air an hour,” comments Peter Teel, sales and marketing manager for SFS Storm Firefighting Support.
He explains that this piece of equipment is especially suitable for older tunnels where there are no inbuilt ventilation fans.
European legislation specifies that any new tunnels should have built-in PPV fans, however, many older ones lack them, a factor which puts them at higher risk of accidents, due to narrow lanes and restricted access for emergency service vehicles and an unforgiving infrastructure without any barriers between the concrete.
“In these kind of tunnels without any ventilation, there is no chance of reaching the seat of the fire. The SVU offers the firefighting teams the chance to blow the smoke one way and attack the fire from the other way,” reports Peter.
“Personally, I think the SVU is a fantastic piece of equipment. In general I think PPV has really increased in popularity in the last couple of years. It took some time to catch on.
“I think it is imperative that you know what you are doing when using this technique, because I heard some stories from the early days where people positioned their units incorrectly and increased the intensity of the fire,” he says.
Peter points out that when anyone rents or buys the SVU, dedicated training is included in the service package.
“You have to know exactly where you aim the fan and where the oxygen is going, because consequences can be disastrous.”
More info? Please e-mail: info@resqtec.com.
