diff --git a/src/main/java/cr0s/warpdrive/render/RenderOverlayAir.java b/src/main/java/cr0s/warpdrive/render/RenderOverlayAir.java
index 97bcdf7b..fd76236b 100644
--- a/src/main/java/cr0s/warpdrive/render/RenderOverlayAir.java
+++ b/src/main/java/cr0s/warpdrive/render/RenderOverlayAir.java
@@ -1,8 +1,13 @@
 package cr0s.warpdrive.render;
 
 import cr0s.warpdrive.BreathingManager;
+import cr0s.warpdrive.api.ExceptionChunkNotLoaded;
+import cr0s.warpdrive.block.breathing.BlockAirShield;
 import cr0s.warpdrive.data.CelestialObjectManager;
 import cr0s.warpdrive.data.CelestialObject;
+import cr0s.warpdrive.data.StateAir;
+
+import javax.annotation.Nonnull;
 
 import javax.annotation.Nonnull;
 
@@ -10,14 +15,19 @@ import net.minecraft.block.state.IBlockState;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.Gui;
 import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.BlockPos.MutableBlockPos;
 import net.minecraft.util.math.MathHelper;
 import net.minecraft.world.IBlockAccess;
+import net.minecraft.world.World;
 
 import net.minecraftforge.client.GuiIngameForge;
 import net.minecraftforge.client.event.RenderGameOverlayEvent;
 import net.minecraftforge.client.event.RenderGameOverlayEvent.ElementType;
+import net.minecraftforge.fml.common.eventhandler.EventPriority;
 import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
 import net.minecraftforge.fml.relauncher.Side;
 import net.minecraftforge.fml.relauncher.SideOnly;
@@ -49,11 +59,7 @@ public class RenderOverlayAir {
 		}
 		
 		// get air stats
-		final boolean hasVoidNearby = isVoid(entityPlayer.world, x, y, z)
-		                           || isVoid(entityPlayer.world, x - 2, y, z)
-		                           || isVoid(entityPlayer.world, x + 2, y, z)
-		                           || isVoid(entityPlayer.world, x, y, z - 2)
-		                           || isVoid(entityPlayer.world, x, y, z + 2);
+		final int rangeToVoid = getRangeToVoid(entityPlayer, x, y, z);
 		final boolean hasValidSetup = BreathingManager.hasValidSetup(entityPlayer);
 		final float ratioAirReserve = BreathingManager.getAirReserveRatio(entityPlayer);
 		
@@ -62,7 +68,8 @@ public class RenderOverlayAir {
 		
 		// show splash message
 		int alpha = 255;
-		if (hasVoidNearby || entityPlayer.ticksExisted < WARNING_ON_JOIN_TICKS) {
+		if ( rangeToVoid >= 0
+		  || entityPlayer.ticksExisted < WARNING_ON_JOIN_TICKS ) {
 			if (!hasValidSetup) {
 				alpha = RenderCommons.drawSplashAlarm(width, height, "warpdrive.breathing.alarm", "warpdrive.breathing.invalid_setup");
 			} else if (ratioAirReserve <= 0.0F) {
@@ -119,10 +126,60 @@ public class RenderOverlayAir {
 		GlStateManager.disableBlend();
 	}
 	
-	private boolean isVoid(final IBlockAccess blockAccess, final int x, final int y, final int z) {
-		final BlockPos blockPos = new BlockPos(x, y, z);
-		final IBlockState blockState = blockAccess.getBlockState(blockPos);
-		return blockState.getBlock().isAir(blockState, blockAccess, blockPos) && !BreathingManager.isAirBlock(blockState.getBlock());
+	private int cache_rangeToVoid = -1;
+	private int cache_ticksVoidCheck = -1;
+	private int getRangeToVoid(@Nonnull final EntityLivingBase entityLivingBase, final int x, final int y, final int z) {
+		if (entityLivingBase.ticksExisted == cache_ticksVoidCheck) {
+			return cache_rangeToVoid;
+		}
+		cache_rangeToVoid  = getRangeToVoid_noCache(entityLivingBase.world, x, y, z);
+		cache_ticksVoidCheck = entityLivingBase.ticksExisted;
+		return cache_rangeToVoid;
+	}
+	private int getRangeToVoid_noCache(@Nonnull final World world, final int x, final int y, final int z) {
+		final MutableBlockPos mutableBlockPos = new MutableBlockPos(x, y, z);
+		final IBlockState blockStateSelf = world.getBlockState(mutableBlockPos);
+		if (isVoid(blockStateSelf, world, mutableBlockPos)) {
+			return 0;
+		}
+		for (final EnumFacing enumFacing : EnumFacing.HORIZONTALS) {
+			// check the block directly next
+			mutableBlockPos.setPos(x + enumFacing.getXOffset(),
+			                       y + enumFacing.getYOffset(),
+			                       z + enumFacing.getZOffset() );
+			final IBlockState blockStateClose = world.getBlockState(mutableBlockPos);
+			if (isVoid(blockStateClose, world, mutableBlockPos)) {
+				return 1;
+			}
+			final StateAir stateAirClose = new StateAir(null);
+			try {
+				stateAirClose.refresh(world, mutableBlockPos.getX(), mutableBlockPos.getY(), mutableBlockPos.getZ());
+			} catch (final ExceptionChunkNotLoaded exceptionChunkNotLoaded) {
+				return -1;
+			}
+			
+			// skip if we're sealed, not in an air lock
+			final boolean isNonAirShieldSealer = !stateAirClose.isAir()
+			                                  && !(blockStateClose.getBlock() instanceof BlockAirShield);
+			if (isNonAirShieldSealer) {
+				continue;
+			}
+			
+			// check 1 more block away
+			mutableBlockPos.setPos(x + 2 * enumFacing.getXOffset(),
+			                       y + 2 * enumFacing.getYOffset(),
+			                       z + 2 * enumFacing.getZOffset() );
+			final IBlockState blockStateFar = world.getBlockState(mutableBlockPos);
+			if (isVoid(blockStateFar, world, mutableBlockPos)) {
+				return 2;
+			}
+		}
+		return -1;
+	}
+	
+	private boolean isVoid(@Nonnull final IBlockState blockState, @Nonnull final IBlockAccess blockAccess, final BlockPos blockPos) {
+		return blockState.getBlock().isAir(blockState, blockAccess, blockPos)
+		    && !BreathingManager.isAirBlock(blockState.getBlock());
 	}
 	
 	@SubscribeEvent