31-10-2012, 04:26 PM
Circuit and Safety Analysis System (CSAS),
F1 Track Design and Safety .doc (Size: 353.5 KB / Downloads: 21)
INTRODUCTION
Success is all about being in the right place at the right time ….. and the axiom is a guiding principle for designers of motorsport circuits. To avoid problems you need know where and when things are likely to go wrong before cars turn a wheel –and anticipating accidents is a science.
Take barriers, for example, there is little point erecting them in the wrong place –but predicting the right place is a black art. The FIA has developed bespoke software, the Circuit and Safety Analysis System (CSAS), to predict problem areas on F1 circuits.
Where and when cars leave circuits is due to the complex interaction between their design, the driver’s reaction and the specific configuration of the track, and the CSAS allows the input of many variables-lap speeds, engine power curves, car weight changes, aerodynamic characteristics etc –to predict how cars may leave the circuit at particular places. The variables are complex. The impact point of a car continuing in a straight line at a corner is easy to predict, but if the driver has any remaining control and alters the car’s trajectory, or if a mechanical fault introduces fresh variables, its final destination is tricky to model.
Modern tyre barriers are built of road tyres with plastic tubes sandwiched between them. The side facing the track is covered with conveyor belting to prevent wheels becoming snagged and distorting the barrier. The whole provides a deformable ‘cushion’ a principle that has found its way to civilian roads. Barriers made of air filled cells, currently under investigation may be the final answer. Another important safety factor is the road surface. Racing circuits are at the cutting edge of surface technology, experimenting with new materials for optimum performance.
TRACK DESIGN
The tracks used in motor sport all are designed to meet certain standards. If a new circuit will ever be used for an international event, its design and layout must be approved by the FIA, before any construction commences. For a permanent circuit, a member of the FIA must inspect it no more than 90 days before a World Championship event, giving adequate time to implement changes.
All design criteria, for curves and straight sections, do not mean the actual track itself, but the actual trajectory followed by the cars whilst racing. Track width on a permanent circuit should be at least 12 metres and should not exceed 15 metres. This avoids bad congestion in corners by limiting the width of the approach to the corner, and having a wide enough track through the corners. There should be 3m minimum clear space along both sides of the track, usually consisting of grass. The maximum length of any new permanent circuit should not exceed 7km to allow drivers to be able to familiarize themselves with all corners on the track. The minimum length of a Formula One circuit will not be less then 3.5km, with the race being no longer than 2h45min. Cross fall across the track for drainage purposes should not exceed 3%, or be less than 1.5%, either from edge to edge or from the centerline to each edge.
The geometry of the track should be designed using the formulae set out by the FIA in Appendix O to the International Sporting Code section 7. These formulae give design criteria for longitudinal profile, visibility, curves, track edges, runoff areas and starting grid specifications. Curves must not get tighter as the turn progresses unless the speed through the corner is less than 125kph, and should preferably have an increasing radius. The maximum number of cars allowed to start in an international race takes all the above geometrical constraints into account, along with the types of cars competing. The number of cars allowed to practice is 20% greater than the number actually allowed to start.
The criterion for barrier placement is stated in section 8 of the above code. If "the probable angle of impact is less than 30o then a continuous, smooth, vertical barrier is preferable, and where the probable angle is high, a system of deceleration (eg. gravel bed) and stopping (eg. tyre barrier) devices should be used." (FIA Appendix O, in appendix 2)
Emergency response.
The emergency response during a motor sport event is one of the most important aspects of safety. When all other safety aspects such as vehicle, and track safety have no more to offer a driver, any further help must come from emergency services. It is vital that drivers can be extracted from damaged vehicles and given the best possible medical care as soon as possible. The 'Recommendations for the supervision of the road and emergency services, Appendix H to the International Sporting code', states the FIA procedures in detail, which will be only covered briefly here.
Any international event should be supervised from a race control centre. This room should be in contact with all marshaling and observation point at all times, and should also have access to emergency services from outside the race such as a helicopter for an evacuation. The Clerk of the Course supervises all emergency procedures from here, after personally ensuring the road is clear of obstacles, is closed to the public and that all observers, marshals and emergency personnel and equipment are in the correct positions.
There must be enough observers placed around the track such that all sections of the road can be constantly monitored. Each observation post must be able to communicate by sight with the posts on either side and must be no more than 500m from each other. These observers must be protected from the vehicles and debris but still able to access the track quickly in the event of an emergency. Every post must have communications equipment, a set of flags, oil absorbing material, brooms, spades and fire extinguishers. At least one of the observers must be trained in first aid. The observers must warn drivers of any adverse track condition, report any incident to race control and maintain a section of track and return it to race condition following an incident.
The observers communicate with drivers by using flags. Yellow flags indicate danger, red flags indicate that the race has been stopped prematurely, a yellow flag with red vertical stripes indicates deterioration in adhesion such as oil or a pool of water, a green flag indicates an all clear after a yellow. A white flag indicates a slow moving vehicle ahead, a blue flag indicates to a slower car that they are about to be lapped. A black flag with a white number indicates that the car with that number must stop in the pits on the next lap, an orange circle on the black flag indicates a serious mechanical problem that may endanger other drivers. A black and white flag divided diagonally shown with a number is a warning for unsportsmanlike behaviour, it is shown only once. All the warning flags can be shown stationary, waved or in the case of yellow, double waved depending on the danger ahead or the urgency of the message. In poor visibility, coloured lights may replace the flags. The use of yellow, blue and white flags are at the discretion of the flag marshals, while the clerk of the course must authorize all others. The marshals must ensure that they do no exaggerate or under emphasize the danger ahead, to ensure the drivers will always respect the flag signals.
If it is necessary to temporarily stop racing, but not stop the race, a safety car is used. This car has yellow flashing lights in its roof and takes control of the race when directed by the Clerk of the Course. No cars may overtake another, or the safety car unless directed by the safety car to do so. If allowed to pass, the car must continue at a reduced speed until it catches the rear of the line of cars behind the safety car. The safety car will only be brought out in the event of a major incident requiring course workers on the track and emergency vehicles on the track, such as tow trucks and ambulances. While the safety car is out, the track is on a full course yellow, with a single yellow flag being displayed at every observation point.
In the event of an accident, two marshals must be on the spot almost immediately, each with a fire extinguisher, fire being the number one priority. Medical crews cannot work in fire and the fire marshals are not permitted to move an injured driver. They must clear the track of debris and oil. A fire-fighting unit should be next on the scene and be able to completely extinguish any remaining fire. The medical crews should be next, arriving as quickly as possible to stabilize an injured driver. A manned portable fire extinguisher should be placed every 150m along the track, with unmanned extinguishers every 50m in between. Marshal’s post should have reserve fire extinguishers. As well as portable fire extinguishers, it is recommended that every 300m, there is an installed fire extinguisher of 60kg capacity with a 200m hose. The extinguishant must be able to be released quickly, leave no slippery residue, have minimum effect on visibility, have low toxicity and be highly effective. BCF (Diflourochlorobromomethane) extinguishers are most commonly used.
The race tracks must have a medical management system with all necessary resources for first aid care. It should provide medical transport in and around the circuit with provision for evacuation to a hospital. Any hospital that may be receiving injured drivers must have a pre-arranged signed contract to supply and have waiting, at least a traumatology specialist, an emergency abdominal specialist and an emergency vascular specialist. For international Formula races there must be a permanent medical centre, usually near the race control building. During a race meeting, at least two anesthetists/resuscitation doctors and two surgeons skilled in spinal injuries and trauma must staff the medical centre. One of the doctors should also be skilled in the treatment of burns. Depending on the level of the medical centre, the response crews and the track design, it may be necessary to have a helicopter waiting and running for the entire race meeting. The track should be equipped with Fast Medical Intervention Vehicles (FMIV) carrying all necessary medical equipment. It must be powerful enough to carry out the first lap behind the field with out being caught by the leaders. The driver must be an experienced race driver, the passenger must be a Doctor trained in resuscitation. The extrication team must have all the necessary equipment to extract an injured driver from a damaged vehicle as quickly and safely as possible.