The effects of the dipole and quadrupole fringe fields on such machine
parameter as chromaticity, anharmonicity, closed orbit, etc. are inve
stigated by stepwise ray-tracing in the Version 4 of the LHC ring. Fir
st the ray-tracing method is described, and the relevant LHC fringe he
ld data and corresponding numerical models are given. Then follows a d
etailed study of the machine parameters which shows the innocuity of t
he non-linearities introduced by the fringe fields, at injection condi
tions.