A pressure regulator, comprising: a regulator body defining an inlet, an outlet, and an orifice disposed between the inlet and the outlet; a plurality of housings coupled to the regulator body, wherein each of the plurality of housings comprises: a lower housing that defines a lower chamber; an upper housing that defines an upper chamber; and a first diaphragm disposed between the lower housing and the upper housing and separating the respective lower chamber from the respective upper chamber; wherein the regulator body forms at least a portion of a lower housing of a first housing defining a first one of the lower chambers, and wherein each of the housings is in flow communication with one another and the regulator body; wherein the lower chambers (208, 208a) are fluidly coupled to an outlet pressure of the pressure regulator; a stem at least partially disposed in the plurality of housings, wherein the stem defines a first aperture and a second aperture, the first aperture being fluidly coupled to the outlet pressure, and the second aperture being fluidly coupled to atmosphere; a plug operatively coupled to the stem via a regulator stem, the plug being engageable with the orifice and arranged to control a flow from the inlet to the outlet; and a plurality of second diaphragms, each of the plurality of second diaphragms disposed between adjacent ones of the plurality of housings, wherein the stem is coupled to the first diaphragm and the plurality of second diaphragms; wherein the regulator stem is arranged to disengage from the first aperture of the stem to exhaust excess pressure from the outlet to the atmosphere through the second aperture when the outlet pressure is above a predetermined pressure and the regulator stem is arranged to engage the first aperture of the stem to prevent exhausting through the second aperture when the outlet pressure is below the predetermined pressure. a regulator body defining an inlet, an outlet, and an orifice disposed between the inlet and the outlet; a plurality of housings coupled to the regulator body, wherein each of the plurality of housings comprises: a lower housing that defines a lower chamber; an upper housing that defines an upper chamber; and a first diaphragm disposed between the lower housing and the upper housing and separating the respective lower chamber from the respective upper chamber; wherein the regulator body forms at least a portion of a lower housing of a first housing defining a first one of the lower chambers, and wherein each of the housings is in flow communication with one another and the regulator body; wherein the lower chambers (208, 208a) are fluidly coupled to an outlet pressure of the pressure regulator; a stem at least partially disposed in the plurality of housings, wherein the stem defines a first aperture and a second aperture, the first aperture being fluidly coupled to the outlet pressure, and the second aperture being fluidly coupled to atmosphere; a plug operatively coupled to the stem via a regulator stem, the plug being engageable with the orifice and arranged to control a flow from the inlet to the outlet; and a plurality of second diaphragms, each of the plurality of second diaphragms disposed between adjacent ones of the plurality of housings, wherein the stem is coupled to the first diaphragm and the plurality of second diaphragms; wherein the regulator stem is arranged to disengage from the first aperture of the stem to exhaust excess pressure from the outlet to the atmosphere through the second aperture when the outlet pressure is above a predetermined pressure and the regulator stem is arranged to engage the first aperture of the stem to prevent exhausting through the second aperture when the outlet pressure is below the predetermined pressure. a lower housing that defines a lower chamber; an upper housing that defines an upper chamber; and a first diaphragm disposed between the lower housing and the upper housing and separating the respective lower chamber from the respective upper chamber; wherein the regulator body forms at least a portion of a lower housing of a first housing defining a first one of the lower chambers, and wherein each of the housings is in flow communication with one another and the regulator body; wherein the lower chambers (208, 208a) are fluidly coupled to an outlet pressure of the pressure regulator; a stem at least partially disposed in the plurality of housings, wherein the stem defines a first aperture and a second aperture, the first aperture being fluidly coupled to the outlet pressure, and the second aperture being fluidly coupled to atmosphere; a plug operatively coupled to the stem via a regulator stem, the plug being engageable with the orifice and arranged to control a flow from the inlet to the outlet; and a plurality of second diaphragms, each of the plurality of second diaphragms disposed between adjacent ones of the plurality of housings, wherein the stem is coupled to the first diaphragm and the plurality of second diaphragms; wherein the regulator stem is arranged to disengage from the first aperture of the stem to exhaust excess pressure from the outlet to the atmosphere through the second aperture when the outlet pressure is above a predetermined pressure and the regulator stem is arranged to engage the first aperture of the stem to prevent exhausting through the second aperture when the outlet pressure is below the predetermined pressure.