▁speed ▁to ▁limit ▁the ▁kin etic ▁energy ▁of ▁the ▁moving ▁door ▁to ▁levels ▁de emed ▁safe ▁for ▁disabled ▁users . ▁ ▁Power ▁Ass ist ▁– ▁This ▁is ▁a ▁version ▁of ▁the ▁low - energy ▁operator . ▁It ▁doesn ' t ▁open ▁the ▁door ; ▁instead , ▁it ▁lets ▁the ▁user ▁open ▁the ▁door ▁manually ▁at ▁a ▁reduced ▁force , ▁compared ▁to ▁opening ▁against ▁a ▁standard ▁door ▁closer . ▁It ▁clos es ▁the ▁door ▁with ▁the ▁same ▁speed ▁limitations ▁as ▁a ▁low - energy ▁operator . ▁ ▁Us es ▁ ▁Full ▁Energy ▁operators ▁are ▁typically ▁used ▁on ▁the ▁outside ▁doors ▁of ▁medium - s ized ▁ret ail ▁business . ▁( Lar ger ▁ret ail ▁business es ▁prefer ▁sl iding ▁door ▁operators .) ▁Low ▁Energy ▁operators ▁are ▁typically ▁used ▁where ▁a ▁simple ▁door ▁closer ▁is ▁sufficient ▁for ▁able ▁users , ▁yet ▁it ▁is ▁necessary ▁to ▁add ▁access ▁to ▁disabled ▁users : ▁small ▁business es , ▁apart ments , ▁bath rooms . ▁ ▁Tr igger ing ▁ ▁A ▁door ▁operator ▁may ▁be ▁triggered ▁in ▁various ▁ways : ▁ ▁Appro ach ▁sensor ▁( such ▁as ▁a ▁rad ar ▁sensor ▁in ▁the ▁form ▁of ▁a ▁G unn ▁di ode ▁and ▁W ave guide ) ▁– ▁the ▁door ▁opens ▁when ▁a ▁user ▁approaches ▁it . ▁ ▁P ush button ▁– ▁the ▁door ▁opens ▁when ▁a ▁user ▁press es ▁a ▁button . ▁ ▁P ush - & - go ▁– ▁the ▁door ▁opens ▁fully ▁when ▁the ▁user ▁begins ▁opening ▁it . ▁ ▁Access ▁control ▁– ▁the ▁door ▁opens ▁when ▁an