If a body cannot cool fast enough this way alone, or when the air is warmer than the skin, it resorts to sweating, which dissipates heatmore quickly but at further cost to circulation.

Sweat glands draw water from the bloodstream. The longer that sweating goes on, the less blood volume remains to serve cooling and other body functions, and the greater the risk of experiencing symptoms of heat illness.A150- lb. person performing moderately active work in warm weather, for example, would lose about ¾ quart of water, or 1% of body weight, per hour. At that rate, without replacing any of the lost fluid, one would feel a notable loss of energy and endurance after three hours, have serious fatigue and nausea after six hours, and lose consciousness after eight hours.

Because thirst signals a water deficit only after it begins to affect performance, starting to drink before or early in awork day is safer thanwaiting to feel the need. Small amounts frequently are better than a large amount at once. The amount of water needed to replace loss through sweating is a function of work-strenuosness and pace, weather, and personal physical attributes.

At most vineyards, water in an Igloo® or similar container is available to employees throughout the day.

Observations from two field studies and talks with numerous managers, however, are that production workers tend to visit the Igloo® infrequently,when quite thirsty and that they drink large quantities on each visit. This pattern results in a low volume and poor rate of fluid replenishment during the day.

When workers do not drink as much or often as they need, it is typically because they perceive high “costs” to obtain the water that is provided relative to its value to them. Impediments to Igloo® access can include physical effort, supervisory or co-worker disdain, foregone earnings opportunity when on piece-rate pay, and fear of ingesting microbes from the water or container. For both workers and managers, putting too low a priority on fluid replacement may stem from limited knowledge of how the body generates and copes with internal heat.

Without understanding the reasons behind advice to drink water frequently, workers are not as equipped ormotivated as they should be for their part in combating heat stress, and supervisors are less apt to assist them with logistical support, information, and personal example.

Standard (CA Code of Regulations, Title 8, Chapter 4, Subchapter 7, Group 2, Article 10) now applies to all outdoor workplaces in California, all the time. In brief, it requires employers of peoplewho work outside to provide four things:

1. One quart of drinking water per person-hour for the entire work shift;
2. Ashaded rest area and the opportunity to use it five minutes or more;
3. Training on nine specific topics for all employees, and on an additional two for supervisors; and
4. Written documentation of procedures to be followed in complying with the regulation.

Definitions in the regulation text and interpretations in a Q&A document from Cal/OSHA elaborate on these requirements and instruct enforcement personnel. Regarding water, unless a plumbed or other continuous supply is readily available to workers, the whole amount is to be provided in portable containers either at the beginning of the shift or in stages through a reliable system of replenishment that allows all employees to drink at least one quart per hour.

Employers are considered out of compliance if at any time no drinking water is available, or if the replenishment practice is to wait until either the container is empty or employees request more water. Cal/OSHA sees a replenishment system as unreliable if employees feel pressured to reduce their water consumption in order to conserve for later in the day.

Shade, according to the regulation, is blockage of direct sunlight. It can be provided by buildings, canopies, awnings, “popup” or other temporary structures, and even trees. A shaded area that is too hot to allowthe body to cool is not acceptable. Access to shade is to be permitted at all times to any employee “suffering from heat illness or believing a preventive recovery period is needed” (even prior to any symptoms).

Cal/OSHA has adopted temperaturetriggers in 2009 for portable shade structures to be in place before any worker requests. Inspectors expect to find shade existing and available at the start of a shift if theNationalWeather Service forecasts a daily high above 85º F or immediately if the temperature reaches 90º F.

While it does not specify training methods, Cal/OSHA says that evaluation of compliance will also depend on manner of presentation, and that enforcement personnel will quiz employees in assessing whether an employer has made a good faith effort to convey essential content.

Topics required in training for all employees are:

• Environmental and personal risk factors for heat illness;
• Importance of frequent water consumption, especially when weather is hot and sweating is more than usual;