Lifetime measurements in $b$-hadron decays at LHCb

Precision lifetime measurements of $b$-flavoured hadrons are an important test of the validity of the theoretical tool used to determine $b$-hadrons observables, the Heavy Quark Expansion. Recent measurements of the $B^{+}$, ${\mathrm{\Lambda }}_b^0$, ${\mathrm{\Xi }}_b^{-}$, ${\mathrm{\Xi }}_b^0$ and ${\mathrm{\Omega }}_b^{-}$ hadrons lifetimes are reported. Moreover, several $B^0$ and $B_s^0$ effective lifetime measurements are discussed, as well as a measurement of the decay width difference in the $B^0$ system, $\mathrm{\Delta }{\mathrm{\Gamma }}_d$. All the measurements have been performed using $pp$ collision data collected with the LHCb detector.