Heat Stress + Jobsite Hydration Reference

Why this matters

Heat-related illness sends thousands of construction + service workers to ERs every summer. Worse, dozens die. Roof work, attic work, mechanical rooms, outdoor digging - service trades have constant heat exposure. The tech who recognizes heat stress early stays safe + keeps the crew working. This is the field card.

Heat illness spectrum (mild to severe)

Heat rash:

• Red, prickly skin
• Sweat ducts blocked
• Minor; cool + dry

Heat cramps:

• Painful muscle cramps
• Often legs / abdomen
• Caused by electrolyte loss

Heat exhaustion:

• Heavy sweating
• Weakness, dizziness
• Headache
• Nausea
• Cool, moist skin
• Body temp slightly elevated (100-102°F)
• Mental clarity intact (mostly)

Heat stroke (MEDICAL EMERGENCY):

• Body temp over 104°F
• Hot, dry skin (sweating stops)
• Confusion, irrational behavior
• Slurred speech
• Loss of consciousness possible
• LIFE-THREATENING - call 911

Recognizing symptoms in yourself

You may not realize you're in heat stress. Watch for:

• Excessive thirst (you're already behind on water)
• Feeling unusually tired
• Headache developing
• Slight dizziness when standing
• Reduced concentration
• "Off" feeling
• Decreased urine output (OR dark urine)

When you notice any: STOP. Rest, cool, hydrate. Don't push through.

Recognizing symptoms in crew

Looking at others:

• Pale OR flushed face
• Acting "drunk" (impaired judgment, stumbling)
• Confused
• Quiet (extroverted person becomes silent)
• Lying down
• Stopped sweating in hot environment

If you see these in coworker: act immediately.

First-aid response

Mild (heat rash, cramps, early exhaustion):

• Move to cool / shaded area
• Remove excess clothing
• Hydrate (water + electrolytes)
• Rest
• Apply cool wet cloth to head, neck, armpits

Heat exhaustion:

• Same as above
• Add: spray with cool water; fan
• Monitor; if not improving in 30 min, call 911
• If symptoms worsen OR mental status changes: call 911

Heat stroke (suspected):

• 911 IMMEDIATELY
• Move to cool area
• Aggressive cooling: ice packs to neck / armpits / groin; cool water spray + fan; cool wet sheets
• Don't give fluids (unconscious / impaired swallow)
• Monitor airway + breathing

Heat stroke = death within minutes if untreated. Don't wait + see.

Hydration

Daily intake (no exertion): 64 oz water (~half-gallon)

Working in heat: 4 oz water every 15 minutes (16 oz per hour)

Hot day + heavy exertion: up to 32 oz per hour possible

Electrolytes (sodium, potassium):

• Lost through sweat
• Sports drinks (Gatorade, Powerade)
• Electrolyte tablets / powder (Liquid IV, Nuun)
• Salt + small food intake

Don't drink (during heat exertion):

• Alcohol (dehydrates further)
• Sugary sodas alone (osmotic dehydration)
• Caffeinated beverages excessively (mild diuretic; some is OK)
• Energy drinks (high caffeine + sugar)

Urine color check

Best self-test:

• Light yellow / clear = well hydrated
• Dark yellow / amber = dehydrated; drink more
• Brown = severely dehydrated; rest + rehydrate

Customer's bathroom = quick check during a hot job.

Pre-hydration

Start the day hydrated:

• 16-20 oz water with breakfast
• Continue through morning
• Don't wait until you're thirsty (already behind)

Acclimatization

The body adapts to heat over days / weeks:

• Day 1 in extreme heat = highest risk
• Day 5-7 = significant adaptation
• After 2 weeks = mostly acclimated

OSHA recommends:

• New / returning workers: 20% exposure day 1, increasing by 20% per day
• After absence (week+): repeat acclimatization
• Schedule new workers' first weeks accordingly

Heat hazard control

Engineering:

• Shade structures
• Misting fans
• Cooled rest area
• Equipment cooled if possible
• Modify equipment positioning to allow shaded work

Administrative:

• Schedule heavy work for cooler hours (early AM, late PM)
• Rotate hot/cool tasks
• Mandatory rest breaks
• Buddy system (watch each other)
• Production goal reductions during heat waves

PPE:

• Light-colored clothing (reflects heat)
• Breathable fabrics
• Cooling vests (some use ice packs OR phase-change material)
• Cooling neck wraps
• Wide-brim hat OR baseball cap (sun protection)

Specific hot work scenarios

Attic work:

• Attic temp 130-160°F+ in summer sun
• 20-30 min max before mandatory cool break
• Bring multiple water bottles
• Ice pack in cooler
• Schedule for early AM

Roofing:

• Direct sun + heat radiation from shingles
• Surface temp 150°F+ on dark roof
• White / light shingle work much easier
• Hydration + sunscreen
• Plan around weather forecast

Lawn care:

• Direct sun all day
• Equipment hot (mufflers near body)
• Pesticide PPE (rubber boots, gloves) traps heat further
• Schedule difficult work for cooler hours

Pool service:

• Direct sun
• Reflected sun from water + concrete
• Chemicals + heat = additional fatigue
• Hydration + sunscreen

HVAC outdoor / rooftop:

• Equipment hot
• Direct sun
• Refrigerant work + heat = compound effort

Mechanical / boiler rooms:

• Hot indoors
• Limited ventilation
• High humidity
• Take breaks outside

Sun protection (different but related)

Beyond heat:

• UV exposure (skin cancer risk)
• Sunburn (compounds heat stress)
• Eye damage (sunglasses with UV protection)

Use:

• Broad-spectrum sunscreen SPF 30+ (reapply every 2 hours)
• Long sleeves (light, breathable)
• Wide-brim hat OR neck cape
• Sunglasses

Workers outside daily for years have measurable skin cancer rate elevation. Sun protection is occupational safety.

OSHA standards

General Duty Clause: employer must provide safe workplace; covers heat illness even though no specific federal standard.

OSHA heat illness prevention guidance:

• Provide water
• Provide rest
• Provide shade
• Train workers + supervisors

California Title 8 Section 3395: specific state heat illness standard for outdoor work (water, shade, rest, training, emergency response).

Washington, Oregon, Minnesota, Maryland: state-specific heat standards.

Other states: General Duty Clause applies.

Required gear

For hot-weather work:

• Cooler with ice
• Multiple water bottles (sealed; ice cubes too)
• Electrolyte drink mix OR sports drinks
• Cooling towel (microfiber that holds water)
• First aid kit with heat-specific items
• Phone (charged; emergency)

Worker training

Annual heat-safety training:

• Symptoms recognition
• First aid response
• Hydration importance
• Acclimatization

Train BEFORE the hot season; refresh in early summer.

Customer expectations

Customer may not realize:

• Why job is paused / postponed in extreme heat
• Why tech needs frequent breaks
• Why some work scheduled early AM

Educate briefly + customer respects safety. Most customers don't want a tech with heat stroke on their property.

Underlying medical conditions

Two techs on the same roof in the same heat do not carry the same risk. Some conditions and some medications cut the body's ability to shed heat, and the person carrying them often does not know it.

Conditions that raise heat risk:

• Heart disease and high blood pressure; the body cools by moving blood to the skin, and a compromised heart cannot keep up
• Diabetes; affects sweating, circulation, and the ability to sense early symptoms
• Obesity; more heat produced, more insulation, harder to shed
• Kidney disease; fluid and electrolyte balance is already stressed
• Respiratory conditions including asthma and COPD, especially in humid heat or poor air quality
• Recent illness with vomiting, diarrhea, or fever; the tank starts empty
• Prior heat illness; a person who has had heat stroke is more susceptible for a long time afterward
• Pregnancy
• Older age generally, though fitness matters more than the number

Medications that impair heat tolerance:

• Diuretics (water pills), common with blood-pressure treatment
• Beta blockers and some other blood-pressure drugs
• Antihistamines and many cold remedies, which reduce sweating
• Antidepressants and antipsychotics, several classes of which affect temperature regulation
• Stimulants, including ADHD medication and heavy energy-drink use
• Some diabetes medications

Alcohol the night before still counts. A tech who drank heavily starts the shift dehydrated regardless of how much water they drink at breakfast.

How to handle it without prying. You are not entitled to a worker's medical history, and asking for diagnoses invites both a privacy problem and a discrimination problem. What you can do:

• Tell the whole crew, in training, that these conditions and medications matter, so each person can self-assess
• Make it normal and consequence-free to say "put me inside today" or "I need an extra break"
• Encourage anyone on a new medication to ask their own doctor specifically about working in heat
• Buddy-check on hot days; someone else notices confusion before you do
• Assign the highest-heat tasks (attics, roofs, unconditioned mechanical rooms in summer) to acclimated workers, and rotate

If a worker discloses a condition, treat it as confidential, keep it out of general conversation, and adjust the assignment quietly. Accommodations in this area are usually simple: more frequent breaks, shaded or cooled work, earlier start, or a task swap. That is cheaper than a heat-stroke incident every time.

References

• OSHA Heat Illness Prevention guidance
• CDC NIOSH guidance on heat stress
• Cal/OSHA Title 8 Section 3395
• ACGIH TLVs for heat stress
• Manuall internal: Jobsite Safety Walkthrough, PPE Selection by Task