Emergency shutters down have pressure/temperature difference overlays.

Based on the emergency shutter from Paradise.

code/__HELPERS/game.dm

@@ -398,4 +398,65 @@ datum/projectile_data
 	var/r = mixOneColor(weights, reds)
 	var/g = mixOneColor(weights, greens)
 	var/b = mixOneColor(weights, blues)
-	return rgb(r,g,b)
+	return rgb(r,g,b)
+
+/**
+* Gets the highest and lowest pressures from the tiles in cardinal directions
+* around us, then checks the difference.
+*/
+/proc/getOPressureDifferential(var/turf/loc)
+	var/minp=16777216;
+	var/maxp=0;
+	for(var/dir in cardinal)
+		var/turf/simulated/T=get_turf(get_step(loc,dir))
+		var/cp=0
+		if(T && istype(T) && T.zone)
+			var/datum/gas_mixture/environment = T.return_air()
+			cp = environment.return_pressure()
+		else
+			if(istype(T,/turf/simulated))
+				continue
+		if(cp<minp)minp=cp
+		if(cp>maxp)maxp=cp
+	return abs(minp-maxp)
+
+/proc/convert_k2c(var/temp)
+	return ((temp - T0C))
+
+/proc/convert_c2k(var/temp)
+	return ((temp + T0C))
+
+/proc/getCardinalAirInfo(var/turf/loc, var/list/stats=list("temperature"))
+	var/list/temps = new/list(4)
+	for(var/dir in cardinal)
+		var/direction
+		switch(dir)
+			if(NORTH)
+				direction = 1
+			if(SOUTH)
+				direction = 2
+			if(EAST)
+				direction = 3
+			if(WEST)
+				direction = 4
+		var/turf/simulated/T=get_turf(get_step(loc,dir))
+		var/list/rstats = new /list(stats.len)
+		if(T && istype(T) && T.zone)
+			var/datum/gas_mixture/environment = T.return_air()
+			for(var/i=1;i<=stats.len;i++)
+				if(stats[i] == "pressure")
+					rstats[i] = environment.return_pressure()
+				else
+					rstats[i] = environment.vars[stats[i]]
+		else if(istype(T, /turf/simulated))
+			rstats = null // Exclude zone (wall, door, etc).
+		else if(istype(T, /turf))
+			// Should still work.  (/turf/return_air())
+			var/datum/gas_mixture/environment = T.return_air()
+			for(var/i=1;i<=stats.len;i++)
+				if(stats[i] == "pressure")
+					rstats[i] = environment.return_pressure()
+				else
+					rstats[i] = environment.vars[stats[i]]
+		temps[direction] = rstats
+	return temps

code/game/machinery/doors/door.dm

@@ -1,4 +1,6 @@
 //This file was auto-corrected by findeclaration.exe on 25.5.2012 20:42:31
+#define DOOR_OPEN_LAYER 2.7		//Under all objects if opened. 2.7 due to tables being at 2.6
+#define DOOR_CLOSED_LAYER 3.1	//Above most items if closed
 
 /obj/machinery/door
 	name = "Door"
@@ -8,7 +10,9 @@
 	anchored = 1
 	opacity = 1
 	density = 1
-	layer = 2.7
+	layer = DOOR_OPEN_LAYER
+	var/open_layer = DOOR_OPEN_LAYER
+	var/closed_layer = DOOR_CLOSED_LAYER
 
 	var/secondsElectrified = 0
 	var/visible = 1
@@ -27,11 +31,11 @@
 /obj/machinery/door/New()
 	. = ..()
 	if(density)
-		layer = 3.1 //Above most items if closed
+		layer = closed_layer
 		explosion_resistance = initial(explosion_resistance)
 		update_heat_protection(get_turf(src))
 	else
-		layer = 2.7 //Under all objects if opened. 2.7 due to tables being at 2.6
+		layer = open_layer
 		explosion_resistance = 0
 
 
@@ -226,7 +230,7 @@
 	icon_state = "door0"
 	src.SetOpacity(0)
 	sleep(10)
-	src.layer = 2.7
+	src.layer = open_layer
 	src.density = 0
 	explosion_resistance = 0
 	update_icon()
@@ -250,10 +254,10 @@
 	if(operating > 0)	return
 	operating = 1
 
-	do_animate("closing")
 	src.density = 1
 	explosion_resistance = initial(explosion_resistance)
-	src.layer = 3.1
+	src.layer = closed_layer
+	do_animate("closing")
 	sleep(10)
 	update_icon()
 	if(visible && !glass)

code/game/machinery/doors/firedoor.dm

@@ -1,5 +1,15 @@
 /var/const/OPEN = 1
 /var/const/CLOSED = 2
+
+#define FIREDOOR_MAX_PRESSURE_DIFF 25 // kPa
+#define FIREDOOR_MAX_TEMP 50 // <20>C
+#define FIREDOOR_MIN_TEMP 0
+
+// Bitflags
+#define FIREDOOR_ALERT_HOT      1
+#define FIREDOOR_ALERT_COLD     2
+// Not used #define FIREDOOR_ALERT_LOWPRESS 4
+
 /obj/machinery/door/firedoor
 	name = "\improper Emergency Shutter"
 	desc = "Emergency air-tight shutter, capable of sealing off breached areas."
@@ -8,17 +18,33 @@
 	req_one_access = list(access_atmospherics, access_engine_equip)
 	opacity = 0
 	density = 0
+	layer = DOOR_OPEN_LAYER - 0.1
+	open_layer = DOOR_OPEN_LAYER - 0.1 // Just below doors when open
+	closed_layer = DOOR_CLOSED_LAYER + 0.1 // Just above doors when closed
 
 	var/blocked = 0
+	var/lockdown = 0 // When the door has detected a problem, it locks.
+	var/pdiff_alert = 0
+	var/pdiff = 0
 	var/nextstate = null
 	var/net_id
 	var/list/areas_added
-	var/list/users_to_open
-	
+	var/list/users_to_open = new
+	var/next_process_time = 0
+
 	power_channel = ENVIRON
 	use_power = 1
 	idle_power_usage = 5
 
+	var/list/tile_info[4]
+	var/list/dir_alerts[4] // 4 dirs, bitflags
+
+	// MUST be in same order as FIREDOOR_ALERT_*
+	var/list/ALERT_STATES=list(
+		"hot",
+		"cold"
+	)
+
 /obj/machinery/door/firedoor/New()
 	. = ..()
 	for(var/obj/machinery/door/firedoor/F in loc)
@@ -38,7 +64,6 @@
 			A.all_doors.Add(src)
 			areas_added += A
 
-
 /obj/machinery/door/firedoor/Del()
 	for(var/area/A in areas_added)
 		A.all_doors.Remove(src)
@@ -48,14 +73,47 @@
 /obj/machinery/door/firedoor/examine()
 	set src in view()
 	. = ..()
-	if( islist(users_to_open) && users_to_open.len)
+
+	if(get_dist(src, usr) > 1 && !isAI(usr))
+		return
+
+	if(pdiff >= FIREDOOR_MAX_PRESSURE_DIFF)
+		usr << "<span class='warning'>WARNING: Current pressure differential is [pdiff]kPa! Opening door may result in injury!</span>"
+
+	usr << "<b>Sensor readings:</b>"
+	for(var/index = 1; index <= tile_info.len; index++)
+		var/o = "&nbsp;&nbsp;"
+		switch(index)
+			if(1)
+				o += "NORTH: "
+			if(2)
+				o += "SOUTH: "
+			if(3)
+				o += "EAST: "
+			if(4)
+				o += "WEST: "
+		if(tile_info[index] == null)
+			o += "<span class='warning'>DATA UNAVAILABLE</span>"
+			usr << o
+			continue
+		var/celsius = convert_k2c(tile_info[index][1])
+		var/pressure = tile_info[index][2]
+		if(dir_alerts[index] & (FIREDOOR_ALERT_HOT|FIREDOOR_ALERT_COLD))
+			o += "<span class='warning'>"
+		else
+			o += "<span style='color:blue'>"
+		o += "[celsius]<5D>C</span> "
+		o += "<span style='color:blue'>"
+		o += "[pressure]kPa</span></li>"
+		usr << o
+
+	if(islist(users_to_open) && users_to_open.len)
 		var/users_to_open_string = users_to_open[1]
 		if(users_to_open.len >= 2)
 			for(var/i = 2 to users_to_open.len)
 				users_to_open_string += ", [users_to_open[i]]"
 		usr << "These people have opened \the [src] during an alert: [users_to_open_string]."
 
-
 /obj/machinery/door/firedoor/Bumped(atom/AM)
 	if(p_open || operating)
 		return
@@ -63,7 +121,7 @@
 		return ..()
 	if(istype(AM, /obj/mecha))
 		var/obj/mecha/mecha = AM
-		if (mecha.occupant)
+		if(mecha.occupant)
 			var/mob/M = mecha.occupant
 			if(world.time - M.last_bumped <= 10) return //Can bump-open one airlock per second. This is to prevent popup message spam.
 			M.last_bumped = world.time
@@ -79,12 +137,7 @@
 		user << "<span class='warning'>\The [src] is welded solid!</span>"
 		return
 
-	if(!allowed(user))
-		user << "<span class='warning'>Access denied.</span>"
-		return
-
-	var/alarmed = 0
-
+	var/alarmed = lockdown
 	for(var/area/A in areas_added)		//Checks if there are fire alarms in any areas associated with that firedoor
 		if(A.fire || A.air_doors_activated)
 			alarmed = 1
@@ -100,9 +153,21 @@
 		user << "\The [src] is not functioning, you'll have to force it open manually."
 		return
 
+	if(alarmed && density && lockdown && !allowed(user))
+		user << "<span class='warning'>Access denied.  Please wait for authorities to arrive, or for the alert to clear.</span>"
+		return
+	else
+		user.visible_message("<span class='notice'>\The [src] [density ? "open" : "close"]s for \the [user].</span>",\
+		"\The [src] [density ? "open" : "close"]s.",\
+		"You hear a beep, and a door opening.")
+
 	var/needs_to_close = 0
 	if(density)
 		if(alarmed)
+			// Accountability!
+			users_to_open |= user.name
+			log_admin("[user]([user.ckey]) has opened an alarming emergency shutter.")
+			message_admins("<span class='danger'>[user]([user.ckey]) has opened an alarming emergency shutter.</span>")
 			needs_to_close = 1
 		spawn()
 			open()
@@ -128,38 +193,37 @@
 		var/obj/item/weapon/weldingtool/W = C
 		if(W.remove_fuel(0, user))
 			blocked = !blocked
-			user.visible_message("\red \The [user] [blocked ? "welds" : "unwelds"] \the [src] with \a [W].",\
+			user.visible_message("<span class='danger'>\The [user] [blocked ? "welds" : "unwelds"] \the [src] with \a [W].</span>",\
 			"You [blocked ? "weld" : "unweld"] \the [src] with \the [W].",\
 			"You hear something being welded.")
 			update_icon()
 			return
 
 	if(blocked)
-		user << "\red \The [src] is welded solid!"
+		user << "<span class='danger'>\The [src] is welded solid!</span>"
 		return
 
-
-	if( istype(C, /obj/item/weapon/crowbar) || ( istype(C,/obj/item/weapon/twohanded/fireaxe) && C:wielded == 1 ) )
+	if(istype(C, /obj/item/weapon/crowbar) || ( istype(C,/obj/item/weapon/twohanded/fireaxe) && C:wielded == 1))
 		if(operating)
 			return
 
-		if( blocked && istype(C, /obj/item/weapon/crowbar) )
-			user.visible_message("\red \The [user] pries at \the [src] with \a [C], but \the [src] is welded in place!",\
+		if(blocked && istype(C, /obj/item/weapon/crowbar))
+			user.visible_message("<span class='danger'>\The [user] pries at \the [src] with \a [C], but \the [src] is welded in place!</span>",\
 			"You try to pry \the [src] [density ? "open" : "closed"], but it is welded in place!",\
 			"You hear someone struggle and metal straining.")
 			return
 
-		user.visible_message("\red \The [user] starts to force \the [src] [density ? "open" : "closed"] with \a [C]!",\
+		user.visible_message("<span class='danger'>\The [user] starts to force \the [src] [density ? "open" : "closed"] with \a [C]!</span>",\
 				"You start forcing \the [src] [density ? "open" : "closed"] with \the [C]!",\
 				"You hear metal strain.")
 		if(do_after(user,30))
-			if( istype(C, /obj/item/weapon/crowbar) )
-				if( stat & (BROKEN|NOPOWER) || !density)
-					user.visible_message("\red \The [user] forces \the [src] [density ? "open" : "closed"] with \a [C]!",\
+			if(istype(C, /obj/item/weapon/crowbar))
+				if(stat & (BROKEN|NOPOWER) || !density)
+					user.visible_message("<span class='danger'>\The [user] forces \the [src] [density ? "open" : "closed"] with \a [C]!</span>",\
 					"You force \the [src] [density ? "open" : "closed"] with \the [C]!",\
 					"You hear metal strain, and a door [density ? "open" : "close"].")
 			else
-				user.visible_message("\red \The [user] forces \the [ blocked ? "welded" : "" ] [src] [density ? "open" : "closed"] with \a [C]!",\
+				user.visible_message("<span class='danger'>\The [user] forces \the [ blocked ? "welded" : "" ] [src] [density ? "open" : "closed"] with \a [C]!</span>",\
 					"You force \the [ blocked ? "welded" : "" ] [src] [density ? "open" : "closed"] with \the [C]!",\
 					"You hear metal strain and groan, and a door [density ? "opening" : "closing"].")
 			if(density)
@@ -170,7 +234,50 @@
 					close()
 			return
 
+// CHECK PRESSURE
+/obj/machinery/door/firedoor/process()
+	..()
 
+	if(density && next_process_time <= world.time)
+		next_process_time = world.time + 100		// 10 second delays between process updates
+		var/changed = 0
+		lockdown=0
+		// Pressure alerts
+		pdiff = getOPressureDifferential(src.loc)
+		if(pdiff >= FIREDOOR_MAX_PRESSURE_DIFF)
+			lockdown = 1
+			if(!pdiff_alert)
+				pdiff_alert = 1
+				changed = 1 // update_icon()
+		else
+			if(pdiff_alert)
+				pdiff_alert = 0
+				changed = 1 // update_icon()
+
+		tile_info = getCardinalAirInfo(src.loc,list("temperature","pressure"))
+		var/old_alerts = dir_alerts
+		for(var/index = 1; index <= 4; index++)
+			var/list/tileinfo=tile_info[index]
+			if(tileinfo==null)
+				continue // Bad data.
+			var/celsius = convert_k2c(tileinfo[1])
+
+			var/alerts=0
+
+			// Temperatures
+			if(celsius >= FIREDOOR_MAX_TEMP)
+				alerts |= FIREDOOR_ALERT_HOT
+				lockdown = 1
+			else if(celsius <= FIREDOOR_MIN_TEMP)
+				alerts |= FIREDOOR_ALERT_COLD
+				lockdown = 1
+
+			dir_alerts[index]=alerts
+
+		if(dir_alerts != old_alerts)
+			changed = 1
+		if(changed)
+			update_icon()
 
 /obj/machinery/door/firedoor/proc/latetoggle()
 	if(operating || !nextstate)
@@ -178,6 +285,7 @@
 	switch(nextstate)
 		if(OPEN)
 			nextstate = null
+
 			open()
 		if(CLOSED)
 			nextstate = null
@@ -189,15 +297,17 @@
 	return ..()
 
 /obj/machinery/door/firedoor/open(var/forced = 0)
-	if (!forced)
-		if (stat & (BROKEN|NOPOWER))
+	if(!forced)
+		if(stat & (BROKEN|NOPOWER))
 			return //needs power to open unless it was forced
 		else
 			use_power(360)
+	else
+		log_admin("[usr]([usr.ckey]) has forced open an emergency shutter.")
+		message_admins("<span class='danger'>[usr]([usr.ckey]) has forced open an emergency shutter.</span>")
 	latetoggle()
 	return ..()
 
-
 /obj/machinery/door/firedoor/do_animate(animation)
 	switch(animation)
 		if("opening")
@@ -213,6 +323,14 @@
 		icon_state = "door_closed"
 		if(blocked)
 			overlays += "welded"
+		if(pdiff_alert)
+			overlays += "palert"
+		if(dir_alerts)
+			for(var/d=1;d<=4;d++)
+				var/cdir = cardinal[d]
+				for(var/i=1;i<=ALERT_STATES.len;i++)
+					if(dir_alerts[d] & (1<<(i-1)))
+						overlays += new/icon(icon,"alert_[ALERT_STATES[i]]", dir=cdir)
 	else
 		icon_state = "door_open"
 		if(blocked)
@@ -220,7 +338,6 @@
 	return
 
 
-
 /obj/machinery/door/firedoor/border_only
 //These are playing merry hell on ZAS.  Sorry fellas :(
 /*